Technologies for Ocean Exploration
Sponsored by Ministry of Earth Sciences, Govt. of India
Jointly organised by Ocean Society of India & National Institute of Ocean Technology OSICON-11
OSICON 11 is the second national conference of Ocean Society of India (OSI) to be held during 13-15, July 2011 at National Institute of Ocean Technology (NIOT). OSI always believes in building partnerships and this time we had the privilege of having NIOT as our partner. OSICON 11 is thus jointly conducted by OSI and NIOT. The focal theme chosen for this conference is “Technologies for Ocean Exploration” and hence NIOT is the right choice for conducting this conference, since it is the premier institute of ocean technology in our country. You might remember that we conducted our previous conference OSICON 09 at Visakhapatnam in March 2009 with partnership of Andhra University. Since the inception of Ocean Society of India (OSI) in 2006, we have been receiving tremendous support and cooperation in furthering the R&D work in marine sciences, engineering and technology. Over these years, OSI built strong bonding with several pioneering institutions like NIO, NPOL(and sister labs of DRDO), NIOT, SAC, INCOIS, NRSC, IOM, Indian Navy, IIT-Kharagpur, IIT-Madras, IIT-Delhi, IISc, Cochin University of Science & Technology, Goa University, Jadavpur University, Anna University and Andhra University. OSI has its life members spread across length and breadth of our country from all of the institutions mentioned above. One of the greatest strengths of OSI is its young research scholars and students who are willing to take part in our activities. We look forward to build more partnerships in future also.
A broad range of topics of current interest is covered for OSICON 11. The various themes on which papers will be presented are Autonomous Underwater Vehicles, Remotely Operated Vehicles, Ocean Engineering, Safety & Reliability, Sonar Technologies, Ocean Observation Systems, Ocean Remote Sensing & Applications, Ocean State Forecasting (Ocean Modeling), Ocean Dynamics, Coastal Processes & Coastal Zone Management, Marine Ecosystems, Bio-geochemistry of Oceans and Atmosphere & Oceans. A total of one hundred and seventeen (117) papers have finally been selected for the conference after peer reviewing all the abstracts received. We have arranged the review of abstracts by inviting the technical subject experts to a common venue and completed the review process. We are extremely grateful to all the technical committee members and other subject experts who assisted for the review of abstracts. Especially the services rendered by Dr K Ravindran, Dr MR Santha Devi, Dr KV Sanil Kumar, Dr GVM Gupta, Dr KK Balachandran, and Shri OR Nanda Gopan are very much appreciated. Dr K Rajith and Shri PSV Jagadeesh have contributed quite significantly in organising abstracts and for bringing out the compendium of abstracts of OSICON 11. As the time available for oral presentations is limited (even with parallel sessions) iii we encouraged all the paper presenters to prepare the posters also, in addition to oral presentations, for display at the conference venue. It gives an opportunity to delegates in extending their discussions even after completion of their oral presentations. Apart from these papers there are six invited talks for this conference by eminent experts in key areas of marine science, engineering and systems.
Dr Shailesh Nayak, Secretary, Ministry of Earth Sciences has given lot of encouragement and guidance in organising this conference. Both the organisations, OSI and NIOT, are grateful to him for all the help rendered in organising OSICON 11. Deliberations of this conference will certainly help understanding of our oceans better and lead to state-of-the-art ocean technologies for future. We thank all the delegates of this conference for their continued interest and enthusiasm for our OSICON series.
Dr CVK Prasada Rao Chairman, Technical Committee OSICON-11
iv National Advisory Committee Dr. Shailesh Nayak Secretary, MoES Chairman Dr. M. A. Atmanand Director, NIOT, Chennai Co-Chairman Dr. Ajit P. Tyagi Director General, IMD Member Dr. S. R. Shetye Director, NIO, Goa Member Dr. Rasik Raveendra Director, NCAOR, Goa Member Dr. V. Bhujanga Rao Director, NSTL, Visakhapatnam Member Shri. S. Anantha Narayanan Director, NPOL, Kochi Member Dr. R. R. Navalgund Director, SAC, Ahmedabad Member Dr. S. K. Dube Emeritus Professor, IIT, Delhi Member Dr. D. Sen Professor, IIT, Kharagpur Member Dr. V. Sundar Professor, IIT, Madras Member Dr. Satheesh C. Shenoi Director, INCOIS, Hyderabad Member Dr. P. V. Joseph President, OSI Convener
Technical Committee Dr. C.V.K. Prasada Rao Scientist, NPOL, Kochi Chairman Dr. K. Ravindran Former Director, CIFT, Kochi Co-Chairman Shri. V. Chander Former Director, NPOL, Kochi Advisor Dr. G. Latha Scientist, NIOT, Chennai Member Dr. M. Sudhakar Scientist & Advisor, MoES Member Dr. M.R. Santha Devi Former Scientist, NPOL, Kochi Member Dr. A.D. Rao Professor, IIT, New Delhi Member Dr. M.R. Rameshkumar Scientist, NIO, Goa Member Dr. K.V. Sanil Kumar Scientist, NPOL, Kochi Member Shri. O.R. Nanda Gopan Scientist, NPOL, Kochi Member Dr. K. Rajith Scientist, NPOL, Kochi Member Shri. P.S.V. Jagadeesh Scientist, NPOL, Kochi Member
Local Organising Committee
Dr. B.K. Jena Scientist, NIOT, Chennai Chairman Dr. M. Harikrishnan Scientist, NPOL, Kochi Co-Chairman Dr. G. Latha Scientist, NIOT, Chennai Member Dr. S. Ramesh Scientist, NIOT, Chennai Member Shri. A.N. Subramaniam Scientist, NIOT, Chennai Member Dr. P. Nammalwar Rajan Project Leader, IOM Anna Univ. Member
v Contents
INVITED TALKS
1 Strides in Deep Sea Technologies – Indian Experience 02 Dr. M. A. Atmanand
2 Indians Estuaries: Need for Concerted Action 03 Dr. Satish R. Shetye
3. Coastal Processes and Management with particular reference to 04 SW coast of India Dr. N.P. Kurian
4. Role of Ocean Atmospheric Process over the Tropical Indian Ocean 05 on the Monsoon Activity over the Indian Sub Continent: A Study Using Remote Sensing Data Dr. M.R. Ramesh Kumar
5. The influence of Oceans on Indian Summer Monsoon 06 Dr. P. V. Joseph
6. Coastal Surveillance and Harbour Protection 07 Dr. J. Narayana Das
vi Ocean Society of India OSICON Proceedings 13-15 July 2011
THEME-1 AUTONOMOUS UNDERWATER VEHICLES AUV-1 Effect of Armour Configuration on Strength Characteristics of 10 Underwater Tow Cables Sameer Abdul Azeez, Anshath Hussain N., K. Sudarsan AUV-2 Underwater Terrain Mapping with a 5-DOF AUV. 10 Shikha, S. K. Das, D. Pal, S. Nandy, S. N. Shome, Soma Banerjee AUV-3 Identification and tracking of objects by Autonomous Underwater 12 Vehicle for Coastal Surveillance Anubhav Sahoo, Siddhant Agarwal and Dhaval Prajapati AUV-4 Hydrodynamic Design of an Underwater Towed System 13 Roni Francis and K.Sudarsan AUV-5 Dynamic Model for Maneuverability and Controllability Studies of AUVs. 14 Debabrata Sen AUV-6 Role of Depressors In Two Part Towed System - A Simulation Study 15 Minu Paulose, K Ajithkumar, K Sudarsan AUV-7 Naukaa – An Automated System to Measure Water Quality Parameters 15 T.Suresh, Madhubala Talaulikar, S.G. Prabhu Matondkar, Aneesh Lotlikar THEME-2 REMOTELY OPERATED VEHICLES ROV-1 Performance of Electrical Power System of Remotely Operable 18 Submersible (Rosub 6000) in KG Basin & Central Indian Ocean Basin Deep Sea Trials. Subramanian AN, Harikrishnan G, Muthukumaran D, Elangovan S, Vadivelan A, Ramadass. G.A, Atmanand MA ROV-2 Characteristics of Intermediate water mixing phenomena in 18 Indian Ocean recorded from the Dissolved Oxygen Optode of ROSUB 6000 – ROV S.Ramesh and G.A.Ramadass ROV-3 Dual mode operation of ROV-500: Design & Control Aspects 20 Sambhunath Nandy, Sankar Nath Shome, Dibyendu Pal, Chandan Har and Pratik Saha ROV-4 Deep water sampling tool design and integration with Work Class 21 ROV – ROSUB 6000 J.Manecius Selvakumar, S.Ramesh, D.Sathia Narayanan, S.B.Pranesh, E.Chandrasekar, M. Murugesh, Radhakrishnan and C. Jothi
Ocean Society of India vii THEME-3 OCEAN ENGINEERING, SAFETY AND RELIABILITY OESR-1 Development of a ship weather-routing algorithm and its application 24 to the north Indian Ocean region Chinmaya P. Padhy and Debabrata Sen OESR-2 A Study of Reliability and Safety on Dynamic Positioning System of 25 ORV Sagar Nidhi D.Rajasekhar, N.Ravi and Anantha Krishna Rao OESR-3 Development and testing of model suction piles in the NIOT test pond 26 Vijaya Ravichandran, R.Ramesh, J.Manecius Selvakumar, Muthukrishna Babu, G.A.Ramadass and M.V. Ramanamoorthy OESR-4 A New Concept and Design of a Low Cost Wave Energy Converter 28 Pradip Deb Roy and Debabrata Sen THEME-4 SONAR TECHNOLOGIES ST-1 Finite element analysis of vibration isolation module with nylon rope 30 strength member Beena.B.R, M. Sabu Sebastian, Manojkumar and S.Jithu ST-2 Reverberation Measurements of Acoustic Tank 31 A.Malarkodi and Dhanalakshmi ST-3 Application of Wavelets for Analysing Ship Noise from shallow water 31 ambient Noise Measurements M. Ashokan, P. Edwards Durai and K.Nithyanandam ST-4 Acoustic Intensity fluctuations induced by environmental parameters 32 in coastal waters Sanjana M C, G Latha and A.Thirunavukkarasu ST-5 Measured broadband reverberation characteristics in Deep ocean 33 Baiju M Nair, M Padmanabham and M P Ajaikumar ST-6 MATLAB code for tow characteristics of an underwater towed system 34 Ambily Vijayan, K Ajith Kumar and K Sudarsan THEME-5 OCEAN OBSERVATION SYSTEMS OOS-1 Analysis on Under Water Seismic Event on June 12, 2010 recorded by 36 Indigenous Tsunami Early Warning System M .Arul Muthiah, Tamil Mugilan, R.Venkatesan OOS-2 Analysis of Antenna placement on Data Buoy Systems for 37 INMARSAT Satellite Communication K.Ramesh, M. Arulmuthiah, P. Murugesh, R.Venkatesan OOS-3 An ARGO Based Study on the Water Mass Characteristics of the 38 Bay of Bengal and the Arabian Sea Sourav Sil, Sudip Jana and Arun Chakraborty viii Ocean Society of India OSICON Proceedings 13-15 July 2011
OOS-4 Coastal wave measurement using HF Radar 39 Manu P. John, Rajnish Antala, Sisir K. Patra and B. K. Jena OOS-5 Inter-comparison of wave measurement by Accelerometer and 40 GPS buoy in shallow water off Cuddalore, east coast of India. Sisir K Patra, B K Jena and K M Siva Kholundu THEME-6 OCEAN REMOTE SENSING & APPLICATIONS ORSA-1 Validation of Satellite Derived Precipitation Data 42 Abdulla C.P. and M.R. Ramesh Kumar ORSA-2 Sea level and eddy kinetic energy variability in the Bay of Bengal from altimetry 43 K.Palanik Kumar and P.P. Saheed ORSA-3 Potential Fishing Zone advisories- Are they beneficial to the coastal 44 fisherfolk?- Kerala experience V.N.Pillai and Preetha.G.Nair ORSA-4 Sea Surface Temperature estimation for condenser coolant 44 discharges from a power plant using satellite data C. Anandan, R. Kaviyarasan, M. Sankar Ram, P.Sasidhar and V. Balasubramaniyan ORSA-5 Upwelling in the southeastern Arabian Sea as evidenced by Ekman mass 45 transport using wind observations from OCEANSAT–II Scatterometer Smitha, A., Ajith Joseph, K., Chiranjivi Jayaram and A. N. Balchand ORSA-6 Sources of Errors in the Measurements of Underwater Profiling Radiometer 46 Noah S, T Suresh, Madhubala T, Bhushan P, Prabhu M and Aneesh L ORSA-7 Change Detection Studies of Rameswaram Island, India Using Remote 47 Sensing and GIS R.Gowthaman, G.S. Dwarakish, V. Sanil Kumar and P. Vinayaraj THEME-7 OCEAN STATE FORECASTING (OCEAN MODELING) OSF-1 Modeling of coastal inundation due to storm surges: 50 A case study for Andhra coast P L N Murty, A D Rao and S K Dube OSF-2 Numerical simulation and mechanism of mini-cold pool off the 50 southern tip of India during summer monsoon season. A D Rao and D K Mahapatra OSF-3 Numerical Hindcasting of storm waves during LAILA cyclone using 51 reanalyzed wind fields. Arun Kumar, S.V.V., K.V.S.R. Prasad, K.V.K.R.K. Patnaik, Ch. Venkata Ramu, P.S.N. Acharyulu, D. Mani kumari and A.P.V. Apparao OSF-4 Numerical simulation of cyclone movement using high resolution Regional 52 Ocean model: A case study for the cyclone MALA (24-29 April, 2006) Bishnu Kumar and Arun Chakraborty
Ocean Society of India ix OSF-5 Indian Ocean Simulation Results from NEMO Global Ocean Model 53 Imran M. Momin, Ashis K. Mitra, D. K. Mahapatra and L. Harenduprakash OSF-6 Time lagged Multiple Linear Regression Model Using Key Indices 54 of SST Fluctuations for Smaller Domains of Oceans Anbarasan, M. R., S. Sundararajan, B.K. Jena, B. Vijay Bhaskar and S. Chandrasekaran OSF-7 Wave forecast from wind parameters using Genetic Algorithm: 55 A case study for the Bay of Bengal A D Rao, Mourani Sinha and Sujit Basu OSF-8 Simulations of tropical cyclone generated storm surges over North 56 Indian Ocean using advanced coastal hydrodynamic model Maria Antonita. T, Remya P.G and Rajkumar OSF-9 Ocean Surface Forcing from AGCM:Medium Range Systematic Errors 57 for Monsoons D. K. Mahapatra, A. K. Mitra, E. N. Rajagopal, Imran Ali and L. Harendu Prakash OSF-10 Assimilation of significant wave height from EnviSAT in coastal wave 58 model using optimum interpolation at variable wave height ranges Suchandra A. Bhowmick, Raj Kumar and Sutapa Chaudhuri OSF-11 Development of an automated Coupled Atmosphere-Ocean Modeling 58 System and Its Application for the Kalpakkam Region SubbaReddy Bonthu, Kaushik Sasmal, Hari.V.Warrior and Prageesh, A. G. OSF-12 Validation of Eddy Viscosity Model in the Laboratory 59 Subhendu Maity and Hari V. Warrior OSF-13 Indian Ocean Response to Windforcing Using LCS Model 60 Surenda, M. OSF-14 Doubling of Tsunami wave while at the sea shore: an analytical study 61 Ramkrishna Datta OSF-15 An implementation of Optimal Interpolation for wave height analysis 62 over Indian waters Sasikala, N. and S.A. Sannasiraj OSF-16 Wave Hindcasting using Artificial Neural Network with varying input 63 Parameter J. Vimala and G. Latha OSF-17 Altimetry and drifter data assimilation in an Indian Ocean circulation model 64 Manisha Santoki, K. N. Joshipura, Smitha Ratheesh, Rashmi Sharma and Sujit Basu OSF-18 Tsunami Inundation Modelling and Mapping along Marina Beach, 65 Chennai Using Cartosat-1 Data Kankara, R. S., S. Chenthamil Selvan, Tune Usha and V. Ram Mohan x Ocean Society of India OSICON Proceedings 13-15 July 2011
OSF-19 Sensitivity Study of Near-shore Wave induced Setup during an 66 Extreme Event in the Bay of Bengal Prasad K. Bhaskaran and A.G. Prajeesh THEME-8 OCEAN DYNAMICS OD-1 Barrier Layer Formation In The Bay of Bengal as Observed by 68 Omni Buoys During Northeast Monsoon Simi Mathew, G. Latha and R. Venkatesan OD-2 Spatial and Temporal Variation of Heat Content in the Upper 69 70m layer of the Arabian Sea Gopika. N and Sajeev. R OD-3 Influence of Indian Ocean Dipole (IOD) on Northeast Monsoon 70 K.N.Navaneeth and M.R.Ramesh Kumar OD-4 Influence of IOD events on sea surface height variability and 71 circulation characteristics along the south - west coast of India Phiros Shah and R Sajeev OD-5 Water Mass Characteristics of the Andaman Sea 71 Sudip Jana and Arun Chakraborty OD-6 Seasonal cycles of heat budget components during the contrasting 72 years of 2004 and 2007 Muraleedharan, P.M., Keerthi, M.G., Nisha, P.G. OD-7 Sea breeze induced wind sea generation and growth in the central 74 west coast of India during pre-monsoon season V.M. Aboobacker, P. Vethamony, M. Seemanth OD-8 The role of Thermal inversions on Hydro-physical processes along 75 the coastal waters off Visakhapatnam, East coast of India Sridevi, T., Maneesha, K. and V.V.S.S. Sarma OD-9 Variability of near-surface temperature fields on Intra-seasonal to 76 inter-annual time scales in the south eastern Arabian Sea (SEAS) Nisha Kurian, V.V.Gopalakrishna, R.R.Rao, S.Amritash, Lix John and C.Revichandran OD-10 Influence of Mesoscale Eddy on Vertical Mixing and Spreading of 77 Water Mass in the Arabian Sea Maheswaran, P.A. Dominic Ricky Fernandez and J. Swain OD-11 Characteristics of Bay of Bengal Water mass in the South Eastern 77 Arabian Sea during 2001-2002 Nageswara Rao G., K Anil Kumar, PSV Jagadeesh and P Anand OD-12 Air-sea interactions and upper ocean thermal structure variations 78 during different epochs of MALA Cyclone over Bay of Bengal Naresh Krishna Vissa, A.N.V. Satyanarayana, and B. Prasad Kumar
Ocean Society of India xi OD-13 Implication of Empirical Orthogonal Function Analysis to Objectively 79 Analyzed Ocean Temperature Data of Bay of Bengal Tarumay Ghoshal, Sudip Jana and Arun Chakraborty OD-14 Dynamics of intraseasonal thermocline variability in the Tropical Indian 80 Ocean during 2004 Bhasha M. Mankad, Rashmi Sharma, Sujit Basu and P. K. .Pal OD-15 Effect of Sea ice melting on the mixed layer depth variation in the 80 Indian Ocean Sector of the Southern Ocean Pranab Deb, Mihir K. Dash, P. C. Pandey THEME-9 ATMOSPHERE & OCEANS – CLIMATE CHANGE AOCC-1 Response of Aerosol Optical Depth (AOD) to the general cycle of 82 global climate in the western and eastern Indian Ocean. Shalin Saleem, KV Sanilkumar, CA Babu and CVK Prasada Rao AOCC-2 Effects of Atmospheric Interferences on Coastal HF Radar Measurements 82 Rajnish Antala, Manu P John and B. K. Jena AOCC-3 On the Relative Roles of Onset Vortex and Mini Warm Pool over the Arabian 83 Sea on the Monsoon Onset over Kerala Ramesh Kumar, M.R. and Syam Sankar AOCC-4 Climate Change and Its Impacts on Marine Fisheries 84 Nammalwar P., S.Satheesh and R. Ramesh AOCC-5 Impact of Rossby waves on the variation of Indian summer monsoon 85 Dhrubajyoti Samanta, M K Dash and P C Pandey THEME-10 (A) MARINE ECOSYSTEMS ME-1 Impact of Coastal Processes and Geomorphology on turtle nesting along 88 Orissa coast, East coast of India P.K. Mohanty, S.K.Patra, B. Seth, U.K Pradhan, B. Behera, S. Barik, P.K. Kar, S. Bramha, P. Mishra and U.S.Panda ME-2 Bacterial Abundance in Godavari Estuary: Influence of River Discharge 89 on Bacterial Metabolism Manjary, D.T., V. R. Prasad, L. Gawade and V.V.S.S. Sarma ME-3 Studies on effects of photosynthetically active radiation in chlorophyll a 90 during post monsoon season off Cochin waters Minu P, S.S Shaju., G. Archana, P. Muhamed Ashraf, B. Meenakumari ME-4 Vertical and Horizontal Distribution of Chlorophyll ‘a’ and Phytoplankton 90 from Pondicherry-Nagapattinam Waters, Southeast Coast of India. Sampathkumar P., K. Kamalakannan, C. Thenmozhi, R. Sankar and T. Balasubramanian ME-5 Seasonality in the Distribution and Abundance of Macrobenthic 91 Fauna in the Cochin Estuary and Adjacent Coastal Shelf. Rehitha, T.V., N. V. Madhu, R. Reshmi, G. Vijay John, C. Revichandran xii Ocean Society of India OSICON Proceedings 13-15 July 2011
ME-6 Plankton metabolic activity and its role on dissolved organic carbon 92 dynamics in a tropical lagoon, Chilika: India K.Vishnu Vardhan, R.S.Robin, Pradipta R Muduli, B.Charan Kumar, A.Lova Raju, D.Ganguly, S.Patra, G.Nageswara Rao, A.V.Raman and B.R.Subramanian ME-7 Influence of Allochthonous Input on Trophic Switch Over and CO2efflux 93 In a Shallow Tropical Lagoon Chilika Lagoon, India Robin, R.S., Pradipta R. Muduli, K.VishnuVardhan, B. Charan Kumar, Shoji D. Thottathil, U.S.Panda, Sivaji Patra, T. Balasubramanian, A.V. Raman and B.R. Subramanian ME-8 Estimating Chlorophyll-a Concentration Using First - Derivative 94 Spectra in Coastal Waters of Bay of Bengal Along East Coast of India Gopala Reddy, K., Srikanth Ayyala Somayajula, B. Srinivasa Rao ME-9 Application of a Ecosystem Model to Study the Dynamics of Nutrients in 95 Chilika Lagoon Uma Sankar Panda, Sivaji Patra, R.S. Robin, K.VishnuVardhan, Pradipta R. Muduli, D. Ganguly and B. R. Subramanian ME-10 Distribution of Benthic Polychaete Species and Relation with 95 Biogeochemical Factors in East Coast of India Naidu, S.A. and V.V.S.S. Sarma ME-11 Meso-Scale Atmospheric Events Promote Phytoplankton Blooms in 96 The Coastal Bay of Bengal Maneesha, K. and V.V.S.S. Sarma ME-12 Environmental factors controlled by phytoplankton biomass and 97 production rate in the estuarine waters off Cochin Dayala V.T and Sujatha C.H ME-13 Diurnal variation of plankton in Godavari estuary 98 Bharathi, M.D.,V. Venkataramana and V.V.S.S. Sarma ME-14 Influence of River Discharge on Phytoplankton Community Structure 99 in the Coastal Bay of Bengal Bandhopadhyay D., T. Acharyya and V.V.S.S. Sarma ME-15 Development of Water Quality Index for Coastal Region of Visakhapatnam 100 using Statistical Techniques Sangeeta Pati, M. K. Dash, C. K. Mukherjee and B. Dash ME-16 River Discharge: A Critical Factor Controlling Phytoplankton Biomass 101 and Community Composition in Monsoon Driven Godavari Estuary Acharyya T., D.Bandyopadhyay and V.V.S.S. Sarma ME-17 Coastal and off shore Phytoplankton Pigment Profile of North Bay of 102 Bengal with reference to TSM and Turbidity Sanghamitra Palleyi, R. N. Kar and C. R. Panda
Ocean Society of India xiii ME-18 Spatial Distribution of Zooplankton along Orissa Coast in Dry Season 103 Suchismita Srichandan, N. C. Rout and C. R. Panda ME-19 Oscillating environmental responses of the eastern Arabian Sea 104 Vijay John Gerson, Madhu. N. V, Jyothibabu. R, Balachandran. K. K, Maheswari Nair, Revichandran C. THEME-10 (B) BIO-GEO CHEMISTRY OF OCEANS BCO-1 Variability of DMS and its Related Compounds in East Coast of India 106 Viswanadham, R., V.D. Rao and V.V.S.S. Sarma BCO-2 Temporal Variability of Dissolved Inorganic Carbon Budget from a 106 Tropical Shallow Lagoon, Chilika, India Prdipta.R.Mudulia, K.Vishnu Vardhan, R.S. Robin, B. Charan Kumar, A.Chandra Mouli, U.S.Panda, Sivaji Patra, G.Nageswarara Rao, A.V.Raman, B.R. Subramanian BCO-3 Source and Fate of Terrestrial Organic Carbon in Sediments along the 107 East Coast of India Krishna, M.S.R., V.V.S.S. Sarma, Lata G, SA Naidu, Ch V Subbaiah, P Praveen Kumar BCO-4 Seasonal Trends in the Aerosol Components over the Cochin Estuarine System 108 Jose Mathew, Gayathree Devi and Sujatha, C.H. BCO-5 Seasonal variation in physico - chemical parameters in relation to organo 109 chlorine pesticides in the Cochin Estuary Salas.P.M. and Sujatha, C.H. BCO-6 Spatial and Vertical transmission Pattern of Pigments and their 110 Assimilation with Nutrients in the Southern Ocean (SO) water mass Sujatha C.H., Akhil P.S., Deepulal P.M., Sini Pavithran, Sharon B. Noronha, N. Anil Kumar. BCO-7 The distribution of REE’s along South coast of India 111 Deepulal, P.M, Gireesh Kumar. T.R. and Sujatha. C.H. BCO-8 Distribution of Labile Organic Carbon in the Godavari Estuary and 111 Adjacent Ground Waters B.S.S. Kumar, V.R.Prasad and V.V.S.S. Sarma BCO-9 Variability of Trace Gases in the Godavari Estuary: Influence of 112 Ground Water Exchange Durga Rao, G., V.D. Rao and V.V.S.S. Sarma BCO-10 Organic carbon modification in the dam reservoir to support 113 heterotrophic carbon demand in the Godavari estuary Prasad, V. R. , B.S.K. Kumar and V.V.S.S. Sarma BCO-11 Stable Isotopes of Carbon and Nitrogen in Suspended Matter and 114 Sediments from the Godavari Estuary Subbaiah, C.V., S. A. Naidu and V.V.S.S. Sarma xiv Ocean Society of India OSICON Proceedings 13-15 July 2011
BCO-12 Sources of Particulate Organic Carbon and Nitrogen in the Gautami 114 Godavary Estuary Lata Gawade and V.V.S.S.Sarma BCO-13 Seasonal Variation of Water Quality Parameters at Puri, East Coast 115 of India-a Pollution Study Baliarsingh, S.K., M.K Khadanga, and K. C Sahu BCO-14 Dredging Impacts on the Coastal Water Quality of Dhamra, Orissa 116 Seoul Sangita, D.R., Satapathy, R.N. Kar and C.R.Panda BCO-15 Suspended matter induced nutrient biogeochemistry in a river plume 117 dominated tropical shallow lagoon Chilka, India. Sivaji Patra, R.S. Robin, Prdipta.R.Muduli, K.Vishnu Vardhan, U.S.Panda and B.R. Subramanian THEME-11 COASTAL PROCESSES & COASTAL ZONE MANAGEMENT CPCZM-1 Hydrodynamic and dispersion modeling of coastal tropical lagoon: 120 a case study in Chilika lagoon Uma Sankar Panda, V. Ranga Rao, B. R. Subramanian, R. N. Samal and M. M. Mohanty CPCZM-2 Flux measurements at the Cochin Harbour Inlet using Acoustic 120 Doppler Profiler Revichandran, C., K.R. Muraleedharan, V.K. Jineesh, Vijay John Gerson, Shivaprasad Amaravayal and M. Rafeeq CPCZM-3 Impact of mining on the stability of a placer mining beach 121 Rajith, K., N.P. Kurian and V.R. Shamji CPCZM-4 Acoustic Doppler Velocimeter Measurements of Surf Zone 122 Currents Along Visakhapatnam-Gangavaram Coast. Ranga Rao, V., S.V.V., Arun kumar, K.V.S.R.Prasad, Ch Venkata Ramu, K.V.K.R.K Patnaik and M. Manikandan CPCZM-5 Intra-Annual Varibility of Wave Characteristics at a Nearshore 123 Location in West Coast of India Jossia Joseph, K. and B. K. Jena CPCZM-6 Assessment of Shoreline Changes of Chennai, Tamil Nadu Using 124 GIS (3d Vectorisation) and Digital Image Processing Techniques Kankara, R. S., B. Rajan, S. Chenthamil Selvan, V. Ram Mohan CPCZM-7 Management of Shoreline Morphological Changes Due to Breakwater 125 Construction along a Stable Coast Noujas, V., K.O.Badarees, N.R.Ajeesh, L.Sheela Nair, T.S.S.Hameed and K.V.Thomas
Ocean Society of India xv CPCZM-8 Investigation of Geomorphic processes on Mulky - Pavanje 126 Rivermouth, West Coast India Gumageri Nagaraj and Dwarakish G S CPCZM-9 Enhanced stratification during neap tide of Godavari Estuary 127 Sridevi, B. V.V.S.S. Sarma and T.V. Ramana Murty CPCZM-10 Role of Bottom Friction in a Tidal Estuary Under Combined 128 Action of Waves and Currents and its Validation Chitra Arora and Prasad K. Bhaskaran CPCZM-11 Prospects for Developing a Minor Port Facility at Betul, Goa 129 Thomas Mathai, Satish Kumar, K.N. Rajarama, P. Praveen Kumar and M. Suresh Chandran. LIST OF OSI LIFE MEMBERS 131 OSI MEMBERSHIP FORM
xvi Ocean Society of India INVITED TALKS IT-1 Strides in Deep Sea Technologies – Indian Experience Dr. M. A. Atmanand Director, National Institute of Ocean Technology, Chennai
Abstract
Development in deep sea technologies in India started very recently. While the naval applications called for deep sea systems up to a depth of 200 metres or less, the advent of deep sea oil availability in the deep sea has resulted in explorations of deep oceans internationally. India has very few institutes working in deep sea technologies and NIOT is the pioneer in this area. Work started way back in end 90’s with the development of underwater crawler mounted sand mining system as part of Poly Metallic Nodule programme of the erstwhile Department of Ocean Development, now Ministry of Earth Sciences. The experience gained while developing the system initially with foreign collaboration, resulted in building up of a strong deep sea technology group in NIOT. This crawler based mining system was later modified by the internal team at NIOT and a refurbished system was designed and tested again for sand mining from on board Ocean Research Vessel, Sagar Kanya. Later the crawler mounted system was re-designed for nodule collection, crushing and pumping to ship. This was tested at a depth of 500m from on board Ocean Research Vessel Sagar Nidhi. Work on system development to mine manganese nodules from a depth of 6000m is currently progressing.
Another deep sea vehicle, Remotely Operable Vehicle (ROV) was designed and developed as part of another programme, tested and qualified up to a depth of 5189 metres at the Central Indian Ocean Basin (CIOB). Even though this was with Russian collaboration, the complete electrical, instrumentation and control system was developed by engineers at NIOT independently.
In order to measure the soil properties in the Central Indian Ocean Basin (CIOB), it is essential to have an instrument, which will measure in-situ bearing strength and shear strength. A soil tester was developed and tested at a depth of 5200 metres in CIOB by the NIOT team.
Many underwater systems and components were indigenized as spin off from the various projects indicated above. Some of them are the underwater fibre optic connector, underwater transformer, underwater thruster etc.
The design features of these and the test results will be covered in detail in the presentation.
2 Ocean Society of India OSICON Proceedings 13-15 July 2011
IT-2 Indians Estuaries: Need for Concerted Action Dr. Satish R. Shetye National Institute of Oceanography, Dona Paula, Goa
Abstract
Well over a hundred estuaries, large enough and important enough to be taken note of, border the Indian coastline. These estuaries have special features that are derived from occurrence of the wet Indian Summer Monsoon (June-September) and hence have been dubbed monsoonal estuaries. High runoff during the wet season and a 8-month long dry season with little runoff lead to striking temporal changes in salinity and velocity fields in these estuaries. Only a handful of these estuaries have been studied to describe their special features.
A number of habitats have adapted to the temporal variability observed in the estuaries. Because the estuaries have been a favoured location for human settlement, anthropogenic impacts on the estuaries have risen sharply. In some cases the impacts are severe because many large cities have grown on banks of the estuaries. However, as yet there has not been a concerted nationwide effort to ensure health of these systems. Such an effort will require gathering of large multidisciplinary data, their analyses, formulation of policy aimed at preservation of health of the estuaries, and implementation of well thought out action plans.
Keeping in view the large number of estuaries that border the Indian coastline, the effort towards data gathering and analyses would be large. Hence, it would be advisable to seek participation of colleges and universities in the effort towards data collection and analysis. The participation need not be restricted to educational institutions already having oceanography as a discipline. New institutions can be roped by imparting short-term training to faculty and students in departments interested in getting involved in environmental issues. In fact, the opportunity of such an involvement offers the prospect of enlarging popular awareness of the problem. This is necessary for legislation for policy formulation to keep the estuaries healthy. In short, concerted action involving government agencies, education and research institutions, and organizations like the Ocean Society of India is need of the hour.
Ocean Society of India 3 IT-3 Coastal Processes and Management with particular reference to SW coast of India Dr. N. P. Kurian Centre for Earth Science Studies, Thiruvananthapuram Abstract
The coasts are dynamic systems, undergoing adjustments of form and processes at different time and space scales in response to oceanographic and geomorphologic factors. Coastal processes can be defined as the set of mechanisms that operate along a coastline, bringing about various combinations of erosion and deposition that in turn influence the geomorphic form and evolution of the coast. The geomorphic form and evolution of coasts are largely controlled by six major factors: waves, tides, offshore topography, bedrock geology, sediment supply and sea-level changes. The coastal zone is constantly under the action of tide, waves, wind and currents and the energy due to these external forces is constantly acting in the coastal zone. Because of this the land water interface along the coastline is always in a highly dynamic state and nature works towards maintaining an equilibrium condition. Dissipation of energy (due to tide, wind, waves and current) is often provided by the beaches, mudflats, marshes and mangroves. Sediment transport is one of the important processes in the coastal zone induced by the hydrodynamic processes. The alongshore and cross-shore transport of sediment as a result of the hydrodynamic processes determine the sediment budget and erosion/accretion status of the coast. In addition to the long and short-term natural processes, there is human interference by building structures for commercial, defence and coastal protection applications and more recently recreational and tourism activities. Coastal development is now causing a significant conflict with natural coastal processes. Knowledge of coastal processes in the area concerned is required to develop strategies for sustainable coastal zone management. The Integrated Coastal Zone Management Plan (ICZMP) is considered to be a tool to manage the problems of the coastal zone and devise a plan for sustainable development. It takes care of sustainable use, development and protection of coastal and marine areas and its resources by ensuring that all sectors and all levels of government are involved in the decision making process. In spite of the availability of a large amount of coastal data from numerous research and technical organisations, significant information gaps still exist. An integrated coastal zone management plan needs to define a long-term sustainable plan, even though that may change with time. There will always be uncertainty associated with considering the long-term, both in terms of extrapolating information and making predictions regarding coastal infrastructure developments, risks, future legislative requirements, opportunities and constraints. Consequently, a primary function of the CZM should be to demonstrate that coastal zone management policies proposed today, i.e. in the short-term, are not detrimental to achievement of a sustainable management plan. The paper presents an overview of the coastal processes of the southwest coast of India and case studies on integrated coastal zone management plan.
4 Ocean Society of India OSICON Proceedings 13-15 July 2011
IT-4 Role OoOcean Atmospheric Process over the Tropical Indian Ocean on the Monsoon Activity over the Indian Sub Continent: A Study Using Remote Sensing Data
Dr. M.R. Ramesh Kumar Scientist, Physical Oceanography Division, National Institute of Oceanography, Dona Paula, Goa Abstract
The southwest monsoon or the summer monsoon which gives about 80% of the mean annual rainfall for the various meteorological subcontinent is one of outstanding meteorological phenomena of the Indian Meteorology [ Ananthakrishnan et al., 1983]. In a typical monsoon season, the monsoon sets in over the Kerala coast by 1st June and covers the entire Indian subcontinent by 15th July. The quantum of monsoon rainfall also varies from year to year. The monsoon rainfall is not continuous within the life cycle of monsoon; there are several spells of active, weak and break in monsoon conditions. The summer monsoon months of June to September contribute 21%, 33%, 28% and 18% of the seasonal rainfall respectively. Thus it can be seen that the mid monsoon months July and August contribute about 61% of the mean seasonal rainfall. Hence, prolonged breaks can in these mid monsoon months can create deficit monsoon or drought like conditions as in the case of 2002, which incidentally had the longest break spell of 34 days according to Ramesh Kumar and Uma [2004]. The air-sea interaction processes over the Indian Ocean are studied using the sea surface temperature from the NOAA/NASA Oceans pathfinder best SST product. The columnar water vapour, wind speed, sensible heat flux, latent heat flux from the recently released high resolution satellite data called Hamburg Ocean Atmosphere Parameters and Fluxes from Satellite (HOAPS) are all examined for contrasting monsoon phases, namely, the active and break in monsoon conditions. The Outgoing Longwave Radiation (OLR) and the rainfall from the Global Precipitation Climatology Programme (GPCP) product were also analysed for the above two contrasting phases. We have used the criteria of Ramesh Kumar and Uma (2004) for identifying the active and break in monsoon conditions for the study period (1988-2010). An analysis of the various air-sea interaction processes over the Indian Ocean for the active (1988, 1989, 1994, 1995) and break in monsoon conditions (1993, 1995, 1999, 2000, 2002, 2009) composite showed that the evaporation rates almost doubled from break to active monsoon conditions over the northern Bay of Bengal. The evaporation rates and integrated columnar water over the northern Arabian Sea were also found to play a vital role during the active monsoon conditions. The winds increased by about 3 m/s higher over these regions during the active monsoon conditions. It was also found that the integrated columnar water vapour above 700 hPa played a major role in the northern Arabian Sea during the active monsoon conditions. The convective maximum (OLR minimum) in Bay of Bengal has also helped in the moisture transport into the subcontinent during active monsoon conditions. In the Eastern Equatorial Indian Ocean (EEIO), the convection was more (less) during the break (active) monsoon conditions.
Ocean Society of India 5 IT-5 The Influence of Oceans on Indian Summer Monsoon Dr. P.V. Joseph Professor Emeritus, Department of Atmospheric Science, Cochin University of Science and Technology, Fine Arts Avenue, Cochin, India
Abstract
Ocean surface temperature maximum has a great control on the location of the Inter Tropical Convergence Zone (ITCZ) in the tropics and the deep cumulonimbus clouds and rain associated with it. Southwest monsoon sets in over India after ITCZ moves across the equator to the northern hemisphere over the Indian ocean. The large scale (spatial) sea surface temperature (SST) anomalies on either side of the equator in Indian and Pacific oceans are found related to the timing of this monsoon onset.
Severe droughts in the Indian monsoon during June to September cause warm SST anomalies over tropical Indian ocean and cold SST anomalies over the west Pacific ocean. These anomalies in the ocean persist till the following monsoon making it give higher rainfall. Thus we do not get in India long runs of drought years as in sub-Saharan Africa, thanks to the ocean.
Recent studies have shown that the Active – Break cycle of the monsoon is the result of ocean – atmosphere interaction on the time scales of 30 - 60 days. We first knew of the large variation in north Bay of Bengal SST on the 30-60 day time scale after NIOT established moored buoy stations there in 1997-1998. We are hopeful that the coupled ocean – atmosphere modelling using high speed computing systems that has just begun in India will help us achieve skillful medium range forecast (two week ahead) of monsoon rainfall of India
In the global warming scenario the SST of equatorial Indian Ocean has warmed much more than the other oceans during the period 1950 to date. This rapid warming of the equatorial Indian Ocean has caused the weakening of the monsoon wind flow through India which has been related to the observed decreasing trend in the frequency of monsoon depressions.
6 Ocean Society of India OSICON Proceedings 13-15 July 2011
IT-6 Coastal Surveillance and Harbour Protection Dr. J Narayana Das Chief Controller R&D (NS&M), DRDO, New Delhi
Abstract
Two thirds of the world population lives within 100 km of the coastline. India has 7000 km of coastline. Major mode of trade depends on maritime operations. We have nearly 200 major and minor ports. Several major national assets such as power plants, shipyards, chemical industries, heavy industries etc are located along the coastline. Apart from that, we have large assets offshore which are also vulnerable targets. Through the sea route enemy can come dangerously close, covertly without any advance warning. The threats are operative all the time, in war and peace. There could be state operators as well as non state players. 24/7 surveillance through multiple sensors, mechanisms to collate data, derive information, effective communication, decision support systems that facilitates quick response to engage and neutralize the threat, all have to be in place.
The threat could be in the form of small boats, fishing crafts, unmanned surface vehicles, AUVs, Divers, swimmers, drifting mines, remote controlled vehicles and the like. The operating zones are generally ports and harbours, where there will always be sizeable congestion of regular traffic of ocean going vessels, including the large number of fishing boats and crafts. While the vessels above 30 m are mandated to have the AIS systems that enable Vessel tracking and Monitoring, the smaller vessels have no such identification, today. Detection, isolation and tracking the activities of suspects of this category needs special efforts and technologies.
Surface threats: Use of Fishing boats, like 26/11 Mumbai Attack, is a major cause of concern. Their detection and isolation from the registered vessels and tracking them down using surveillance radars alone is not practical. There is a need to institute special AIS systems on all registered vessels. Such systems should also provide special services to the crew, such as identifying fishing zone, special help in case of emergency etc so as to motivate them to install and maintain the new system. Looking at the data and the need to further scalability it is necessary to have satellite links of communication, in place. Radar systems capable of resolving 20 m class vessels at a reasonable range of say 10 km, over the sea clutter and all weather conditions itself poses technology challenges. Thermal imagers and high-resolution electro optic systems are also necessary in order to classify, augment and enable decision support systems.
Ocean Society of India 7 Subsurface Threats: Subsurface threats like AUVs and divers are more difficult to be detected and tracked. In the congested coastal zone, detecting small TCS targets using SONARs alone becomes possible only at short ranges. A diver approaching at 0.5m/sec, detected at say 500m, gives just 1000 seconds to resolve, decide and implement action for neutralization. In the case of small AUVs the scenario is still adverse. Mobile detection systems mounted on AUVs that can deploy RF links for communication when an alert is perceived can be used for off coast patrolling. Apprehending suicide attacks, it may be even necessary to neutralize the threat much before the intruder can reach the target installation.
In a broad sense coastal surveillance and harbour protection systems are very complex involving multidisciplinary technologies. Speed in detection analysis, decision and implementation are keys to success.
8 Ocean Society of India OSICON Proceedings 13-15 July 2011
ABSTRACTS
THEME-1 AUTONOMOUS UNDERWATER VEHICLES
Ocean Society of India 9 AUV-1 Effect of Armour Configuration on Strength Characteristics of Underwater Tow Cables Sameer Abdul Azeez, Anshath Hussain N., K. Sudarsan Naval Physical and Oceanographic Laboratory, Thrikkakara, Kochi
Underwater cables used in towed applications like Anti-Submarine Warfare (ASW) or oceanographic research are distinguished by the presence of load-carrying structural armour. The armour acts as the ‘mechanical lines’ of the cable in addition to the electrical lines or electric cum fibre optic lines, resulting in electromechanical and electro-opto- mechanical cables respectively. Depending on the type of the armour material, the tow cables are classified as ‘Heavy Tow Cable’ and ‘Light Tow Cable’. Using metals, generally steel, in the design of the armour lends weight to the cable and renders it negatively buoyant. On the other hand, when materials like aramid are used in armouring, the cable becomes lightweight or neutrally buoyant. The design of the tow cable is a highly specialized area. To a large extent, the failure of the cable during harsh ocean towing conditions is due to the inadequate design of the armour. In a vast majority of the cases, a double-layer contra-helical design is used for the armour, to achieve torque-balance in the cable. This is done by employing opposite lay angle directions in the inner and outer layers of the cable. This paper studies the effects of different types of armour configurations on the strength characteristics of a steel-armoured electro-opto-mechanical cable. Three different double-layer configurations are considered for this heavy tow cable subjected to tensile, torsional and bending loads. Finite element techniques are applied to estimate the effective stresses, changes in diameter, axial strains and reaction torques in the cable. It is found that the cable has a better performance in terms of strength characteristics when the wire diameter of the inner armour layer is higher than that in the outer layer.
AUV-2 Underwater Terrain Mapping with a 5-DOF AUV Shikha, S. K. Das, D. Pal, S. Nandy, S. N. Shome, Soma Banerjee Central Mechanical Engineering Research Institute, Durgapur, CSIR, India
The aim of this paper remains to introduce the extensive application of a state-of-the-art Autonomous Underwater Vehicle (AUV-150) capable of operating up to a depth of 150 meters, without any human intervention. The AUV-150 has been developed to perform seabed mapping and collect oceanographic data like salinity, temperature and conductivity
10 Ocean Society of India OSICON Proceedings 13-15 July 2011 at various depths. In this regard, various functional aspects of the system shall also be discussed in this paper.
The AUV-150 is a cylindrical-shaped carrier with streamlined fairing to reduce hydrodynamic drag. It is embedded with active propulsion, navigation, and control systems. Equipped with a camera, CTD and side scan sonar as payload sensors the AUV- 150 is perfectly designed for performing underwater terrain mapping as well as oceanographic survey activities.
The present paper discusses the navigation and guidance issues on the one hand as well as underwater terrain mapping done at Idukki Lake located at Cochin in Kerala, India on the other. Various mission trials have been conducted at the lake with AUV-150 from 25.09.10 to 09.10.10. Typical lawnmower, square and straight course missions have been conducted towards effective lake-floor mapping and bathymetry. Testing was carried out in a 500 x 500 meter square area with the launching point close to 9.8020 N/ 76.8940 E GPS coordinates. The average altimetry observed was close to 15 meters ranging from as low as 8 meters towards the banks to as high as 26 meters towards the middle of the lake.
The navigational autonomy has been achieved on large scale through the effective coordinated operation of controller, navigational sensors, and actuators, altogether governed by a control software architecture running on a dual core x86 processor with a clock frequency of 2.0 GHz. The positional information from INS has been improvised through integration of GPS as well as DVL data. Since, the GPS is non-functional while underwater, therefore positional data inconsistency from INS up to a specified limit, has been corrected for using dead reckoning technique with DVL data.
A typical deep survey Side-Scan-Sonar (SSS) with 4000 meters standard depth ratings and optimized resolution, data rates and power requirements, matching best with the AUV-150 hardware design specifications, is used as a major payload sensor for mapping underwater terrain. Adopting the latest CHIRP signal processing technique, the SSS, operated at 325 KHz and 657 KHz of frequencies, provides digital data with improved range resolution and sonar images with fine clarity.
Apart from the directly obtained images, the digital data obtained from the lake trails is post-processed using MATLAB to sort out the positional coordinates and the height informations and the sorted data is further manipulated through Non-Uniform Rational B-Spline (NURBS) modeling using OpenGL, with a view towards rendering a 3 dimensional plot of the seabed-contour.
Ocean Society of India 11 AUV-3 Identification and tracking of objects by Autonomous Underwater Vehicle for Coastal Surveillance Anubhav Sahoo, Siddhant Agarwal and Dhaval Prajapati Department of Ocean Engineering and Naval Architecture, Indian Institute of Technology, Kharagpur Nurali Nizar Virani and Siddartha Khastgir Department of Mechanical Engineering, Indian Institute of Technology, Kharagpur
The aim of this paper is to provide a schema for coastal surveillance for AUVs. The proposed work aims to develop the current knowledge base of underwater surveillance and observation techniques using an Autonomous Underwater Vehicle. In this paper, the task of coastal surveillance encompasses three major areas namely Object detection, Object identification and Object tracking. Object identification involves approximately determining the velocity, the heading of the foreign body and to make a log along with photos taken periodically for offline analysis. In this mode, the AUV is static and can only use the pan-tilt setup to track the object as long as it is in the visible range. If the object of interest is to be tracked as per the mission guidelines, the task of pursuit involves path planning based on dynamically changing destination while avoiding obstacles in a 3D space. These tasks are achieved through image processing from a visual input system in real-time and by additional help from proximity sensors. Special considerations in each proposed technique is made for the limited vision range within the marine environment. The obstacle avoidance module has been achieved by the usage of a novel algorithm and it is validated by various test cases.
The two stage implementation of mission planner, global and local planning serve to divide the tasks and follow the modular approach to accomplish a mission. Though, the framework proposed is independent of the type of AUV being used, simulations and test cases have been studied for a differential drive based thrusters for surge motion and a central thruster for heave motion. The paper is concluded by validating the proposed framework for coastal surveillance and discussing the results obtained from various simulations.
Keywords: Static tracking, Path Planning, Obstacle Avoidance, Vision-guided navigation, Coastal Surveillance.
12 Ocean Society of India OSICON Proceedings 13-15 July 2011
AUV-4 Hydrodynamic Design of an Underwater Towed System Roni Francis and K.Sudarsan Naval Physical and Oceanographic Laboratory, Kochi
Cable towed bodies are used in military, paramilitary and civilian applications such as anti-submarine warfare, oceanography and geophysics. A typical towed system comprises of a hydrodynamically designed underwater body housing a payload, towed by a surface ship using an electro-mechanical or electro-opto-mechanical cable. Design of the towed system is a complex process involving consideration of various parameters such as the size and weight of payload, cable forces, spatial geometry of the cable, depth and stability of the towed body in horizontal as well as in vertical plane while in tow.
In the present paper the design of a cable towed system is described. The design requirements include specifications of the cable, size and weight of the pay load, speed and operational depth. The design objective is to evolve the parameters of the towed system such as the cable scope and the dimensional configuration of the towed body such that the towed body is positioned at the required depth of tow for the given speed of the tow ship. Hydrodynamic stability is also addressed in both pitch and yaw planes.
The shape and dimensions of the towed body are determined based on the size of the payload to be housed. The required depth of operation can be achieved by increasing the cable payout or by increasing the area of fin. Hence the optimum values of cable pay out and area of fin are initially determined. The cable geometry and cable tension are determined with the help of Podes tables.
The lift to be generated by the fins of the towed body are then determined based on the required cable tension. The geometry of the fin section is selected based on the NACA profiles. The parameters of the fins such as dimensions, aspect ratio, sweep back angle are then determined.
The stabilizer fins (aft fins) of the towed body are designed based on the requirements of stability in yaw and pitch. The mathematical expressions for the moment coefficients in pitch and yaw are evolved. The parameters of the stabilizer fins such as the aspect ratio, slope of lift curve and area of the fins are varied until desired stability parameters are achieved in both pitch and yaw planes.
Ocean Society of India 13 AUV-5 Dynamic Model for Maneuverability and Controllability Studies of AUVs Debabrata Sen Dept. of Ocean Engineering & Naval Architecture, IIT Kharagpour 721302, India
For the past couple of decades, AUVs of different shapes, sizes, endurance and mission requirements are being developed for exploration of the ocean and its resources all over the world. Several AUVs are also being developed in India. In order to study their maneuverability and controllability aspects and to design suitable control algorithms, appropriate dynamic models are required along with estimation of hydrodynamic and control coefficients. In general, there are three classes of submerged vehicles operating in three different speed and time regimes: (i) torpedoes operating at high speeds for time durations measured in minutes, (ii) submarines operating at mid-speed range for time durations measured in days and months, and (iii) AUVs operating at low-speed range for durations measured in hours. Although all three are submerged vehicles, due to the differences in the speed and time ranges as well as mission requirements, their hydrodynamic behaviour and consequently maneuverability and controllability characteristics are quite different. The dynamic models for the first two types of generic vehicles are quite well established: historically these two types of vehicles were under development for over half a century and the technology is very mature. AUVs on the other hand are relatively new type of underwater vehicles, and because of the low-speed operational requirements, these vehicles have considerably different maneuverability characteristics. In this paper, we discuss development of suitable mathematical model for AUVs and more importantly identify and discuss the associated hydrodynamic coefficients and methods of their estimation. Discussion is also made on appropriateness and usefulness of CFD studies for determining these coefficients, and it is shown that at present, CFD can make estimation of only a very few of the required coefficients, which is insufficient to study maneuverability and controllability aspects of these vehicles.
14 Ocean Society of India OSICON Proceedings 13-15 July 2011
AUV-6 Role of Depressors in Two Part Towed System - A Simulation Study Minu Paulose*, K Ajithkumar, K Sudarsan Naval Physical and Oceanographic Laboratory, Kochi, Kerala, India *National Institute of Technology, Calicut, Kerala, India
An investigation on depth keeping mechanism of a towed system using hydrodynamic and weighted depressor is carried out at different towing speeds and cable payouts. The towed body have to maintain certain constant depth for the effective performance of the sensors, considering ocean parameters. Drag force and tension experienced during towing operation is severely affected by the length of the cable paid out, it is essential to minimise the length of primary tow cable. Hence, the simulation is done at different primary cable payout to predict the optimised cable length that can be used for the system. The simulation was carried out using the numerical tool for three configurations, viz single part towed system, two part towed system with weighted depressor and hydrodynamic depressor. It is observed from the simulation results that a hydrodynamic depressor which is 1/16th weight of weighted depressor gives same depth when towed with same cable payout and tow speed. The advantage of using a hydrodynamic depressor compared to weighted depressor is brought out in this paper.
Keywords:- Depressor, Two part towed system, towed body, flexible module, simulation
AUV-7 Naukaa – An Automated System to Measure Water Quality Parameters T.Suresh, Madhubala Talaulikar, S.G. Prabhu Matondkar, Aneesh Lotlikar* National Institute of Oceanography, Goa *Indian National Centre for Ocean Information and Services, Hyderabad, India
Measurements of water quality parameters of rivers and coastal are essential for monitoring its health. The periodic measurements will allow determining the variability of critical parameters and thus relate their effects on ecology and marine environment, pollution, sediment transport, productivity and related aspects. Naukaa is an in-house developed small portable battery operated automated system that can be operated in a moving canoe to map the water parameters in short span of time. The system comprises of microcontroller, water sampling unit, GPS, data transfer unit and sensors. The
Ocean Society of India 15 microcontroller controls the water-sampling unit, acquires the data from the sensors and GPS and transfers the data to the server and laptop using wireless devices. The sensors that measure parameters include are depth, temperature, salinity, chlorophyll, blue-green- algae, dissolved oxygen and turbidity. Additional sensors can be interfaced with ease. For its operation, Naukaa is placed in the canoe, and as the canoe moves in the river, the water is periodically pumped via a small hosepipe to the unit and after measurements the water is drained off. The data acquired is stored on a flash disk. The data can be downloaded to a laptop or sent to a server on land via wireless devices. Operating Naukaa in the River Mandovi and Zuari provided variations in parameters at high spatial resolution. This low cost system provides an opportunity to study the temporal and spatial variations of water parameters from the coastal waters, rivers, dams and canals with ease and less time.
16 Ocean Society of India OSICON Proceedings 13-15 July 2011
ABSTRACTS
THEME-2 REMOTELY OPERATED VEHICLES
Ocean Society of India 17 ROV-1 Performance of Electrical Power System of Remotely Operable Submersible (Rosub 6000) in KG Basin & Central Indian Ocean Basin Deep Sea Trials Subramanian AN, Harikrishnan G, Muthukumaran D, Elangovan S,Vadivelan A, Ramadass. G.A, Atmanand M.A National Institute of Ocean Technology, Chennai, India
Remotely operated vehicles are the main tools in exploring and exploiting subsea resources. Gas hydrates and poly metallic nodules are major promising resources which are available at different deep sea depths. Exploration and exploitation of the above said resources is a nascent technology. A work class Remotely Operable Submersible (ROSUB- 6000) has been designed and developed at NIOT in joint collaboration with EDBOE, Russia. This paper describes the electrical power system and its performance of ROSUB 6000 in the deep sea trials, KG basin and Central Indian Ocean basin. The paper presents the operating performance of various components of electrical power system of ROSUB-6000 enriched with problems faced during deep sea trials in above said two sites at critical depths. Major electrical components dealt were high frequency high voltage converters, special purpose subsea high frequency transformers, subsea power converters, BLDC motor thrusters and pumps.
ROV-2 Characteristics of Intermediate water mixing phenomena in Indian Ocean recorded from the Dissolved Oxygen Optode of ROSUB 6000 - ROV S.Ramesh and G.A.Ramadass National Institute of Ocean Technology, Chennai
Dissolved oxygen profiles in ocean basin are a useful tracer for tracking the movement of water-types and water masses, especially those in the deep and bottom waters. Dissolved oxygen normally finds in saturation degree in the euphotic layer, and its concentration decreases toward the main thermocline where a minimum concentration layer appears. In marine environments Dissolved Oxygen (DO) availability studies will insight to understand the resultant process of the interplay of physicochemical (atmospheric exchange and mixing) and biological (photosynthetic production and respiration) activities. South Equatorial Current (SEC) is the permanent circulation feature in the
18 Ocean Society of India OSICON Proceedings 13-15 July 2011
Central Indian Ocean Basin (CIOB) which influences the mixing phenomena of intermediate waters. The SEC, in general, extends between 10oS and 16oS and exhibits seasonal (north-south) shifts with its northern boundary moving up to 4oS during southern winter. Vertical flow of water through conveyor belt circulation mechanism takes rich contents of oxygen to deeper waters. This dictates the terms of availability for the organism’s presence in Deep Ocean. Present study deals with the observed temperature, salinity, sound velocity and dissolved oxygen profiles collected during the deep water qualification sea trial of ROSUB 6000 (Remotely Operated Submersible - ROV). ROSUB 6000 is a deep water work class ROV developed at NIOT with design capability to work up to 6000 m water depth. Different phases of sea trial were performed during 2009-2010 and carried out more than 15 dives covering Bay of Bengal, Arabian Sea, Equatorial region and Central Indian Ocean Basin. ROSUB 6000 - ROV is connected with scientific payloads such as Dissolved Oxygen sensor, sound velocity profiler and conductivity sensor for real time data collection apart from other intended activities with cameras, multi-beam sonar and robotic arms. Data collected from ARGO floats are also compared and considered for interpretation to establish the intermediate water circulation phenomena. Dissolved Oxygen profiles indicate second maxima of DO level at a depth of 400 m apart from surface payer. At 400 m depth highest concentration of was recorded (200 µM) at 12.5oS and 75oE which is gradually reducing to less than 50 µM at Arabian Sea (12oN and 75oE). Even though the profiles were available up to the maximum of 5289 m from ROSUB 6000 CIOB sea trial, for the present study data collected upto 1600 m to 2000 m depth at equatorial region and western part of Arabian Sea and Bay of Bengal are compared to arrive up on mixing characteristics of dissolved oxygen in Indian Ocean. Higher concentration of dissolved oxygen in Central Indian Ocean Basin and the dilution of DO concentration due to very low DO content of Arabian Sea water are clearly established by the reduction in concentration. These mixing phenomena may be happening due to the influence of Sverdrup’s Indian Ocean Central Water which is termed as Sub-Antarctic Mode Water (SAMW). This paper deals with the DO, water temperature, salinity and sound velocity vertical profile characteristics recorded from ROSUB 6000 system and ARGO floats and establishes the mixing phenomena of intermediate waters to make second maxima of dissolved oxygen in Central Indian Ocean Basin.
Ocean Society of India 19 ROV-3 Dual mode operation of ROV-500: Design & Control Aspects Sambhunath Nandy, Sankar Nath Shome, Dibyendu Pal, Chandan Har, Pratik Saha Central Mechanical Engineering Research Institute, Durgapur, CSIR-CMERI, India
This paper highlights the detail design and control of a Remotely Operated Vehicle (ROV) up-to a depth of 500m with a maximum forward velocity of 4 knots and payload capacity of 30 kgf. The developed ROV can be manoeuvred under water from an on-ship surface control station autonomously or through joysticks depending on the operational need.
The present ROV is a tethered, open frame mobile robotic system suitable for envisaged shallow water applications with appropriate payload & navigational sensors and multi- thruster based motion controllers. Five numbers of DC brushless thrusters (of 93 kgf capacity each) are mounted in three orthogonal directions to manoeuvre the ROV in water. Two thrusters are mounted horizontally in forward direction to control forward motion (surge & sway) and heading (yaw); two thrusters are mounted in vertical direction to control depth (heave). Roll and Pitch are balanced through mechanical design by judicious placement of the various components.
The key parameters like depth, maximum velocity, overall system dimension, cable diameter are essentially responsible for overall ROV system design and selection of actuators and power systems. The parameters are highly interrelated and overall compact system design is achieved through an iterative procedure. The basic frame of the ROV has been analyzed from deflection point of view through finite element analysis. The system is designed for near neutral buoyant with the help of polyurethane based solid buoyant material.
ROV is interfaced with a slip-ring & winch system with cable handling & cable length measurement facility and fiber-optic based faster and advanced communication link. The ROV is equipped with camera & lamp and side scan sonar as payload sensors. Several sensors like Motion Reference Unit (MRU), Doppler Velocity Log (DVL), depth sensor and altimeter are used as feedback devices for the navigation, guidance and control of the vehicle.
The present ROV can be operated manually and programmatically in autonomous mode. Position control of ROV represents an important class of control problem. The detailed dynamic formulation is very essential for high velocity applications and also to design simple controller with a low cost sensor suite. The overall control system has been
20 Ocean Society of India OSICON Proceedings 13-15 July 2011 decoupled into two sub-systems i.e., planner motion control (surge, sway and yaw) and depth control. The planner motion of ROV system is thought of as a non-holonomic motion control strategy where two actuators are employed to control three degree’s of freedom. A feedback linearization based path following controller with online gain scheduling has been designed to control the ROV through various paths. The control methodology adopted for path tracking overcomes stringent initial condition constraints. The simulation results are very much encouraging and validation through experiments has been planned to be carried out at the earliest. ROV-4 Deep water sampling tool design and integration with Work Class ROV - ROSUB 6000 J.Manecius Selvakumar, S.Ramesh, D.Sathia Narayanan, S.B.Pranesh, E.Chandrasekar, M. Murugesh, Radhakrishnan and C. Jothi National Institute of Ocean Technology, Chennai
Deep water work class Remotely Operated Vehicle (ROV) namely ROSUB 6000 had been developed by NIOT and qualified for its envisaged functionality during April 2010 at a depth of 5289 m in Central Indian Ocean Basin. ROV is interfaced with multi-beam sonar and scientific sensor to measure water temperature, conductivity, dissolved oxygen, dissolved methane and sound velocity to perform scientific deep water exploration. ROV is equipped with two robotic arms (manipulators) having 5 function and 7 function activity to perform intended activities of sampling. Sampling tool interface with ROV is designer of ROV’s innovative idea to make use of available place, power and hydraulics for effective utilization. For sediment sampling ROSUB 6000 is interfaced with in house designed short corer of 40 cm length with 55 mm diameter which will be attached at the bottom frame of ROV. Whenever ROV touches the sea floor after completion of maneuvering operation, short corer will collect the sample and bottom core catcher is designed to hold the collected fine sediments. Same corer with gripper on top of it is used with manipulator arm for collecting the sample like push corer. Sample collection tray of the dimension 690 mm x 320 mm x 250 mm is fixed in front of the ROV and a scoop capable of collecting 750 ml by volume is interfaced with 5 fn manipulator. Whenever ROV reaches the sea floor, by using manipulator camera and front pan & tilt camera, we can sample the sea floor by the scoop mechanism and sample can be stored in the tray. Tray has bottom fine meshes where the water can be drained. Using the available spare port of hydraulic pump a slurp pump mechanism is designed for sampling the top sediments fine material along with 20 mm size biological organisms from the deep sea floor. Collected materials are stored in separate containers. Apart from sediment sampling, niskin water sampler (capacity 5 l) is
Ocean Society of India 21 attached in front of the ROV and the robotic arm itself is used as manual trigger instead of messenger. At appropriate place of important, water sample can be collected for water quality analysis using manipulator by watching the front camera images in deep waters up to 6000 m. Even though the sample collected cannot hold such a high pressure in deep waters, as a first step the collected samples can be effectively used for geo-scientific studies to correlate the visual image observation carried out with cameras at sampling site. Interfaced scientific payloads are tested and qualified during the scientific exploration sea trial for gas hydrate exploration in Krishna-Godhavari Basin in Bay of Bengal at a depth of 1019 m and 1035 m and at Poly-metallic Manganese Nodule site in Central Indian Ocean Basin at a depth of 5289 m. Short corer mounted in ROV had sampled the two pieces of manganese nodule from central Indian ocean basin. Integration of slurp pump is in progress and these sampling tools are useful for many scientific observation. Detail of sampling tools design and integration are discussed in this paper.
22 Ocean Society of India OSICON Proceedings 13-15 July 2011
ABSTRACTS
THEME-3 OCEAN ENGINEERING, SAFETY AND RELIABILITY
Ocean Society of India 23 OESR-1 Development of a Ship Weather-Routing Algorithm and Its Application to the North Indian Ocean Region Chinmaya P. Padhy and Debabrata Sen* Consultant, EDS-E&U/EIT, WIPRO Technologies, Hyderabad, AP-500032, India *Professor, Dept. of OENA & Head, CORAL IIT- Kharagpur, WB-721302, India
Ship weather routing deals with finding an optimal track based on forecasts of weather and sea conditions and the ship’s characteristics in a particular transit. While the weather parameters that influence ship behavior involve waves, currents and wind, the most important attribute in this connection is the prevailing wave-field in the voyage area. Historically ship routing used to be based on long-term climatological data on wave conditions. With advances in the weather and climate modeling coupled with availability of large computing power, it has now become increasingly common to base the route decisions on weather and in particular wave forecasts. It is now possible to use sophisticated wave modeling software like 3rd generation WAM by ship operators using on-board computing systems to forecast wave fields using wind and other satellite generated data, which can be obtained from specific sites.
The term optimal means a route that optimizes any one or a combination of the factors such as maximum safety and crew comfort, minimum fuel consumption, minimum transit time etc., depending on the vessel, voyage type and mission requirements. All these aspects are however influenced by the prevailing weather condition. Weather routing of ships therefore needs to combine (i) a tool to forecast weather (current, wind and in particular wave) conditions, and (ii) assessment of ship behavior in such weather conditions, by means of a suitable optimization algorithm.
Dynamics of ships in waves is a complex theme which is usually referred to as seakeeping characteristics of ships. Increase in resistance due to present of ocean waves for example is a nonlinear phenomenon. In general, ship behavior under the influence of wind, waves and currents can be related to a reduction in speed of the vessel. This reduction can be of two types (i) an involuntary speed reduction, and (ii) a voluntary speed reduction. Typically thus ship routing will be choosing an optimal route depending on the wave conditions so that the prescribed objective function is optimized (i.e. minimized). Djikstra’s path optimization scheme, which employs optimal control theory and dynamic programming technique, is used to obtain optimum route in a given random sea-state.
24 Ocean Society of India OSICON Proceedings 13-15 July 2011
In applying the present algorithm, an area encompassing the voyage area is divided into suitable meshes using lat-long coordinates within which the forecast significant wave height and wave directions using wave-modeling software are generated. The application is presently confined to the routes lying in the North Indian Ocean region due to availability of the forecast wave data using ISRO (Indian) satellite generated information. Based on an assumed form of theoretical wave-spectrum (an ITTC spectrum is usually used for ship applications), the optimal route is then predicted by optimizing a suitable ‘weight’ or ‘achievement’ function, which is determined depending on the ship behavior and weather conditions in that grid. The ship seakeeping characteristics are pre-computed over a range of significant wave height, relative heading and speed using industry-standard strip-theory based software, which is then interpolated to obtain the necessary data for each spatial grid. It is shown that the algorithm is general and versatile enough to consider almost all constraints that are required in a practical application, e.g. presence of land boundaries, handling of non-navigable water, presence of current and wind, storm effects, consideration of voluntary speed-reduction based on a set of seakeeping performance characteristics, etc. A number of results for two ships, a small 60m coastal vessels and a moderately large 180m cargo ship, are presented to demonstrate various aspects of the algorithm.
Technological advances in satellite altimetry offer the possibility for providing timely ocean information which helps to extend the developed algorithm as a function of time for optimizing strategic sea routes.
Keywords: weather-routing, seakeeping, ship-behavior in waves, wave modeling
OESR-2 A Study of Reliability and Safety on Dynamic Positioning System of ORV Sagar Nidhi D.Rajasekhar, N.Ravi and Anantha Krishna Rao Vessel Management Cell, National Institute of Ocean Technology, Chennai, India.
Sagar Nidhi is an ice class multi disciplinary Oceanography Research Vessel (ORV) of National Institute of Ocean Technology, operated and maintained by Vessel Management Cell. She has class-2 dynamic positioning system which automatically controls the vessel, to maintain its position and heading exclusively by means of active thrust. She is utilised for Deep Sea Mining, launching of Remotely Operable Vehicle, Autonomous Underwater Vehicle, manned/unmanned submersibles and exploration of Gas Hydrates so on that needs a highly reliable DP system to carry out the operations for several hours in a
Ocean Society of India 25 particular station. She is capable of carrying out Geo-scientific, Meteorological and Oceanographic research in Indian and Antarctic waters. Drift off or drive off scenarios makes the need for a highly reliable DP system to maintain the station in worst case events. A study has been carried out to get Failure Mode Effect Analysis and reliability of DP system, which is normally affected by failure of subsystems and its components. Potential failure modes and its impacts on performance of DP system are analysed through FMEA and subsequent corrective actions were taken. Failure data of subsystems and its components were used in reliability block diagram which inturn used to find the reliability of DP system. Two main recommendations were suggested i.e. redundant cooler for both Azimuth and Bow thruster are provided along with redundant main propulsion cooler which improves the overall reliability from the current value of 36% to 68%. Based on the study two other recommendations were given to improve the reliability. Use similar material in pipelines to the maximum extent possible to reduce the corrosion and the possible damage and maintain a standard distance and difference in altitude for the antennas of external sensors which reduces the possible failure of subsystem and thereby improved life along with increased reliability is achieved. These actions results in improvement in safety of vessel, onboard machineries, instrument used for scientific research and life of onboard scientist and ship staff.
Keywords:- Reliability, Safety, DP systems, Performance Analysis, Thrusters, Redundancy, Risk Priority Number.
OESR-3 Development and testing of model suction piles in the NIOT test pond Vijaya Ravichandran, R.Ramesh, J.Manecius Selvakumar, Muthukrishna Babu, G.A.Ramadass and M.V. Ramanamoorthy National Institute of Ocean Technology, Chennai
Suction anchors are widely used in mooring applications for floating production units and find widespread applications in the offshore oil industries. Suction pile anchors are large cylindrical (inverted bucket type structure) open at the bottom and closed at the top. Prediction of the uplift capacity of suction caissons is a critical issue faced by the design engineers and rational methods are required in order to produce reliable designs. NIOT has fabricated a prototype suction pile (4.5m long 3m diameter) to develop a methodology for testing and prediction of uplift capacity by carrying out demonstration tests in 100m water depths. Prior to the trial deployment in the offshore locations, a series
26 Ocean Society of India OSICON Proceedings 13-15 July 2011 of model tests were conducted in a field setup in NIOT. Objective of these model tests were to develop methodology, design and logistics for suction pile installation & retrieval before deployment in offshore locations.
Model tests were carried out in the NIOT test pond using model piles of diameter 0.3m to 0.5m by varying the aspect ratio (length to diameter (L/D) ratio). The working platform for deployment testing is located within the pond. A suction pump capable of 2 bar suction (differential) has been developed for the purpose of installation. Suction pressure requirements in sands are significantly higher than in clays. Estimates of suction pressures in sand indicate that higher the diameter of the pile, lower is the suction pressure (differential) requirement. However, in sands, higher suction pressures lead to increased seepage thereby requiring pumps with high flow rates in order to develop the requisite differential pressure. Presently PSG make pump with flow rate of 180 litres/min is proposed to be used. For a given suction pressure, the pump flowrate needs to be in excess of the seepage in order to achieve penetration. Alternatively, the suction pressures may be reduced in order to lower the seepage thereby suiting the pump capacity. Two vents of 65mm diameter are provided at the top for applying suction pressure and delivery. One way flow is maintained through solenoid valves. Additional vents are provided for removal of water during lowering.
The instrumentation consists of thrusters for ensuring verticality and preventing rotation of the anchor during installation, pressure transducers for measuring suction pressure at the vent and pore pressures within the anchor. Depth sensors and altimeter for measuring rate of penetration and pan and tilt sensors equipped with cameras and lights for checking verticality are also installed. The electronics and pump shall be housed on a pump skid which will be connected to the prototype through an emergency release system during deployment. Since the electronics, instrumentation and electrical components are to be protected from exposure to seawater and high pressure at 100-200m water depths, they shall be housed in pressure cases.
Initial tests indicated a pullout capacity of 785kg for a 500mm diameter 750mm long pile while a 300mm diameter 450 long model (L/D=1.5) provided a pullout capacity of 285 kg. For L/D=1 for 300 mm diameter pile, the pullout capacity was 185 kg, while for L/D=2, the capacity was 350 kg. This shall be verified with numerical model tests.
Ocean Society of India 27 OESR-4 A New Concept and Design of a Low Cost Wave Energy Converter Pradip Deb Roy and Debabrata Sen* Dr. B. C. Roy Engineering College, Dist. Burdwan, (West Bengal) *Dept. of Ocean Engineering & Naval Architecture, IIT, Kharagpur, West Bengal
Ocean wave is a vast source of energy which is yet to be fully utilized for the mankind, although at present there exist few methods of exploiting kinetic energy of the wave. In this work, an innovative design of a wave energy converter (WEC) is proposed where the kinetic energy obtainable from the ocean surface wave is converted in the form of potential energy which can subsequently be used for any other useful purposes. The initial configuration and the basic principle of application of this device are tested through simple experimentation. A propagating wave imposing normal force on a submerged vertical thin plate of size 0.8×0.6m causes it to oscillate in the surge direction, and a mechanical system is devised which transforms this motion to potential energy by raising water to a certain height. Two compression spring of spring coil diameter ds = 2mm is attached with the plate at the back side and the plate moves in the direction of ocean wave against the two compression springs. The plate is connected to the piston of size 0.1m diameter, by means of a piston rod of size 0.01m. Piston moves with the motion of the plate in a closed fitting cylinder of internal diameter 0.1m and external diameter 0.12m. Suction and delivery pipes with suction valve and delivery valve are connected to the cylinder. The suction and delivery valves are one way valves which allow the water to flow in one direction only. Suction valve allows water from ocean to the cylinder and delivery valve allows water from cylinder to delivery pipe.
The system is extremely cheap and therefore viable even if the energy transformation is only a small percentage of available wave energy. This can be deployed over large parts of coastal areas having a large and poor population, and the energy stored in form of potential energy can be used for electric power generation driving small motors like irrigation pumps. This paper presents the experimental investigation demonstrating the validity of the concept.
28 Ocean Society of India OSICON Proceedings 13-15 July 2011
ABSTRACTS
THEME-4 SONAR TECHNOLOGIES
Ocean Society of India 29 ST-1 Finite Element Analysis of Vibration Isolation Module with Nylon Rope Strength Member
Beena.B.R*, M. Sabu Sebastian, Manojkumar, S.Jithu Naval Physical and Oceanographic Laboratory, Kochi, India *Mar Athanasius College of Engineering, Kothamangalam, Kerala, India
Vibration isolation modules (VIMs) are used in underwater towed sensor arrays to control the mechanically induced tow noise. In general vibration isolation module has a gel filled cylindrical construction with polymeric outer hose and tensioned polymeric strength member running between end connectors. In the existing configuration of VIM Kevlar fabric is being used as the strength member. This paper focuses on the performance prediction of VIM with Nylon rope as an alternative strength member. The study includes viscoelastic characterization of Nylon rope, estimation of longitudinal vibration response by finite element analysis and experimental validation of the response.
The viscoelastic properties of the major constituent, the Nylon rope, are modeled using discrete parameter models. For comparative purpose, three parameter and five parameter models are employed. The finite element model of VIM in ANSYS mainly comprises of COMBIN 14 discrete parameter models for Nylon rope and SOLID 185 viscoelastic element for polymeric hose and gel. The viscoelastic parameters of Nylon rope strength member are determined through semi-empirical means from strain rate tests at different preloads and at different strain rates. Validation of finite element estimate is done by impact tests.
The paper also presents a comparison between (i) the analytical and experimental results, (ii) the performance of three parameters and five parameters model of Nylon rope, (iii) performance of VIM with Nylon strength member and Kevlar strength member.
Key words: VIM; underwater towed acoustic sensor; ANSYS finite element model; Nylon rope; strength member; viscoelastic.
30 Ocean Society of India OSICON Proceedings 13-15 July 2011
ST-2 Reverberation Measurement of Acoustic Tank A.Malarkodi and Dhanalakshmi National Institute of Ocean Technology, Chennai
The accuracy of acoustic measurements in the acoustic tank depends on the reverberation due to the boundaries. When an acoustic source emits the signal in the measurement tank, these signals are reflected by the walls, the surface and the bottom. The multiple reflections give rise to the reverberant field. The acoustic energy depends on the power of the source and the losses on the walls. In general reverberation time can be defined as the time in seconds for a sound energy to drop 60 dB below its initial value.
The reverberation study was carried out at the Acoustic Test Facility (ATF) of National Institute of Ocean Technology by using the standard projector transducer of known characteristics. The source transducer was driven with different frequencies like 1 kHz, 5 kHz, 10 kHz, 20 kHz and 40 kHz of sinusoidal signals and also driven with white noise. The reverberated field is assumed as homogeneous in space and isotropic. The homogeneity of the reverberated field was verified by taking the measurements at different locations of the tank simultaneously. At time t=0, the sound pressure level at different positions of the tank was measured using data acquisition system with the sampling frequency of 102.4 kHz. Then the slope of the mean square value was found numerically using the sampled output voltage with a sampling frequency. The suitable time of integration was chosen in order to average the signal and to get the decreasing slope. By applying a linear regression the reverberation time was determined. The average reverberation time of the acoustic tank measured was in the range between 350ms and 400ms. This study will be useful for better acoustic measurement in the acoustic tank.
ST-3 Application of Wavelets for Analysing Ship Noise from Shallow Water Ambient Noise Measurements M. Ashokan, P. Edwards Durai and K.Nithyanandam National Institute of Ocean Technology, Pallikaranai, Chennai, India.
Time series measurements of shallow water ambient noise have been made for a week, off Tuticorin by deploying an autonomous ambient noise measurement system. The preliminary analysis of measurements showed predominantly the noise field is due to ship crossing other than the wind noise. This paper presents the work carried out in
Ocean Society of India 31 extraction of specific ship noise sources by application of wavelet transforms as wavelet denoising algorithm has finer decomposition and reconstruction properties in the frequency domain. The frequency localization of wavelet denoising technique is used to efficiently localize the ship noise.
The methodology involves study of spectrogram of the noise measurements initially and then application of wavelet decomposition (down sampling). The optimal threshold value for the wavelet coefficients is calculated and this yields 2(2n-1) levels to denoise the signal. From the wavelet coefficients, reconstruction (up sampling) of the decomposed signal is done. Finally the spectrogram of the reconstructed signal is studied. The results show clearly the narrow band frequency components of shipping noise present. This has applications in finding different types of boats/ship noise and the technique is applied to different data sets for finding such sources.
ST-4 Acoustic Intensity Fluctuations Induced by Environmental Parameters in Coastal Waters Sanjana M C, G Latha and A.Thirunavukkarasu National Institute of Ocean Technology, Chennai, India
In coastal regions various factors affect the propagation of short range acoustic signals such as the wind, tidal effects, off shore currents and even river outflows. Shallow water waveguide is also characterised by site-specific source nature, bathymetry, sediment properties and sound speed profile. A vertical linear array of hydrophones (frequency band 10 Hz - 10 kHz) integrated with mechanical fixtures and data acquisition systems with necessary power pack has been deployed off Cochin to study the ambient noise characteristics at 32 m water depth with a lossy bottom. Data have been collected for longer periods covering wind speeds of 2 - 6 beaufort and the entire spring-neap tidal cycles. Sound velocity profiles and bottom sediment samples measured at the site characterize the water column and the ocean bottom respectively. Due to heavy river influx of fresh water at the site, the sound velocity profile exhibit a well defined negative gradient. The bottom is clay (soft bottom) which can lead to absorption of acoustic intensity into the sediment leading to a decrease in reflected acoustic rays. Under these conditions propagation to large distances will be associated with large losses in acoustic energy. The critical angle of propagation determined theoretically in this case is found to be ±15p with respect to horizontal representing low order trapped modes.
32 Ocean Society of India OSICON Proceedings 13-15 July 2011
In this paper the noise received is compared with respect to the propagation characteristics in the water column, and noise intensity and direction of arrival is determined for different environmental conditions such as a downward refracting sound velocity profile, an upward refracting sound velocity profile and an iso-velocity profile. For an upward refracting sound velocity profile, noise propagation will be along the surface and will lead to predominant noise arrival from the top whereas for downward refracting profile, rays will travel along the bottom and hence noise arrival will be from the bottom. The effect of wind forcing on the water surface and movement of water due to tides causes variability on the acoustic properties, which have also been investigated here. It is also seen that fluctuation in noise property arise due to small and large scale environmental phenomenon which includes sound speed profile fine structure, small scale turbulence and frontal zones.
ST-5 Measured Broadband Reverberation Characteristics in Deep Ocean Baiju M Nair , M Padmanabham and M P Ajaikumar Naval Physical and Oceanographic Laboratory, Kochi, India
Broad band reverberation measurements were collected in deep water (2067m) off Vizag. TNT scare charges (0.450kg) were used as sound sources which were expended from the ship. The signals were recorded using two hydrophones deployed from the ship. The sound speed profile exhibits 63m duct with a limiting ray angle of about 4.47o and lower cut off frequency of 177 Hz. One third octave band analyses using multirate filters and time frequency analysis (spectrogram) were done to study the reverberation characteristics. A sudden fall of 10 dB near ~12-13s on the reverberation characteristic in deep water is related to the effect of sound speed profile and water depth. This effect is correlated with ray theory based model and the results are presented.
Ocean Society of India 33 ST-6 Matlab Code for Tow Characteristics of an Underwater Towed System Ambily Vijayan*, K Ajith Kumar, K Sudarsan Naval Physical and Oceanographic Laboratory, Kochi, Kerala, India *Mar Athanasius College of Engineering, Kothamangalam, Kerala, India
Cable scope, cable tension, cable angle, body depth & body trail for a given speed of vessel are the typical parameters that play an important role in the preliminary design of any underwater towed system. A MATLAB code is developed based on the theory of two dimensional steady state analysis of tow cable. It is assumed that the cable lies in the plane containing the direction of gravity and that of the towing ship’s motion. The free surface effects are neglected and the cable is uniform, moving with constant horizontal velocity. A Graphical User Interface developed makes it user-friendly and quick visualization of the results. The code is useful and handy for any operator of an underwater towed system during field trials.
34 Ocean Society of India OSICON Proceedings 13-15 July 2011
ABSTRACTS
THEME-5 OCEAN OBSERVATION SYSTEMS
Ocean Society of India 35 OOS-1 Analysis on Under-water Seismic Event on June 12, 2010 recorded by Indigenous Tsunami Early Warning System M. Arul Muthiah, Tamil Mugilan, R.Venkatesan National Institute of Ocean Technology, Chennai, India
This paper presents the work carried out on the indigenous development of data acquisition and processing system for the Tsunami buoy with bottom pressure reorder deployed by Ocean Observation Systems of National Institute of Ocean Technology under the Ministry of Earth Sciences of Government of India. The indigenously developed tsunami buoy data acquisition / processing system has interface with the Bottom Pressure Recorder system, Surface Buoy Acoustic Modem, Inmarsat satellite communication Modem etc. The system was deployed on 14th April 2010 in Bay of Bengal at the location TB04 (09 °18.5768’N , 089 ° 27.0692’ E). The Bottom Pressure Recorder (BPR) measures the instantaneous pressure at the sea bed continuously, using 15 second samples and averages the data. In normal mode, at regular intervals (for every 1 hour), the BPR will telemeter an acoustic data message to the surface modem with a time stamped pressure reading along with some status parameters. The Bottom Pressure Recorder compares every sample to a predicted value that is calculated from the previous pressure readings. If the difference between the two exceeds a preset threshold value, the BPR enters into alarm mode and starts to telemeter every sample every 5 minutes for a period of 3 hours, after which it returns to the normal mode. The system was functional in the sea and transmitting data every one hour. On June 12, 2010 when an undersea earth quake occurred, it captured the signal, switching to tsunami mode for three hours and the data recorded by the system has been analyzed. Comparison of the data with the nearby NOAA Buoy (Station: 23401) has been made and results are presented in this paper.
36 Ocean Society of India OSICON Proceedings 13-15 July 2011
OOS-2 Analysis of Antenna placement on Data Buoy Systems for INMARSAT Satellite Communication K.Ramesh, M. Arulmuthiah, P. Murugesh and R.Vengatesan National Institute of Ocean Technology, Chennai, India
Moored buoys have been deployed to record and report a wide range of sub-surface, surface and atmospheric conditions in the Indian ocean. The real time data from these platforms used for advance scientific research, support weather and marine forecasts, and aid climate modelling and prediction. Data from the platform are transmitted to shore station with help of INMARSAT satellite. The INMARSAT antenna for transmission is kept in a mast assemble for better signal strength, buoy mast assembly is prone to get vandalized frequently, this paper describe the study conducted on the placement of antenna inside the FRP hood to protect the antenna from vandalism and its consequences. An experiment was conducted with different strategies, in which one buoy was deployed with antenna inside the FRP hood, and another one was deployed with antenna placed in the mast assembly. This study was carried out with the real time data received from the buoy. The signal strength of the antenna is co-related with buoy reference North and INMARSAT satellite position. This paper discusses further on the strategies to overcome the data transmission problem with the option of antenna placement inside the FRP hood to reduce the incidence/ consequence of vandalism.
Ocean Society of India 37 OOS-3 An ARGO Based Study on the Water Mass Characteristics of the Bay of Bengal and the Arabian Sea Sourav Sil, Sudip Jana and Arun Chakraborty Centre for Oceans, Rivers, Atmosphere and Land Sciences (CORAL), Indian Institute of Technology Kharagpur, Kharagpur, India
This study presents the differences of the water mass characteristics of the two semi enclosed basins: the Arabian Sea (AS) and the Bay of Bengal (BOB) located in the north Indian Ocean. The work based on the Array for Real-time Geostrophic Oceanography (ARGO) datasets for the years 2003 to 2009. Before being used for the study, these ARGO data passed through several quality control procedures such as position on land test, pressure increasing test, regional range test, spike test, gradient test, density inversion test and finally visual inspection for the suspected data. The temperature- salinity (T-S) diagram indicates the existence of the high saline water mass in the AS. The vertical structures of salinity show that the salinity increases with depth for the BOB but for the AS it increases up to certain depth and then again decreases. The depth with maximum salinity (called as core depth) varies from 20m to 80m for the AS. The monthly variation of the core depth shows that it deepens when the salinity is less at the surface. The nature of the annual cycle of surface temperature is similar for the BOB and the AS. But the surface of the BOB is warmer than that of the AS throughout the year expect May. The monthly variation of the surface salinity are similar for both the basins. But surface salinity of the AS is higher than that of the BOB throughout the year. The maximum surface salinity for the AS is found to be 36.5 psu while for the BOB it is 33.4 psu. The monthly variation of surface density is analogous for these two basins but for the AS is higher than that of the BOB.
38 Ocean Society of India OSICON Proceedings 13-15 July 2011
OOS-4 Coastal wave measurement using HF Radar Manu P. John, Rajnish Antala, Sisir K. Patra, B. K. Jena National Institute of Ocean Technology, Chennai - 600100
Measurement of waves at different locations, spatially, for a complete study of a region is not feasible as the effort and the cost for installing individual instruments over a region is enormous. High Frequency (HF) radar can solve this problem to a certain extent by remotely monitoring the wave activity over a region near to the coast. HF Radar is a tool for synoptic on-line mapping of surface current fields and the spatial distribution of the wave directional spectrum. In this study we check the possibility of replacing the Wave rider Buoy with HF Radar along the Tamil Nadu region.
Wave data from two HF Radar sites and two Wave rider buoy along the Tamil Nadu coast is used for the study. In the Indian scenario the average wave height is normally between 1 to 2 m in height along the entire coast, except during the monsoon period. During the monsoon months the wave height reaches to about 2- 3 m with a mixed influence of swell and sea waves. The installed HF Radars are quite adequate to detect the high wave activity. But it is insufficient to detect wave heights less than 1.4 m. The HF Radar wave data obtained during various periods has been analyzed and it co-relates satisfactorily with the maximum wave height (Hmax) obtained from the Wave rider buoy. Thus making it an efficient method to monitor high wave activity along the region covering a large domain of more than 100 km even during a cyclone period, during which a Wave rider buoy may be hard to manage. The measurement of wave height of about 0.4 m can be achieved by using HF radar with high resolution mode.
Ocean Society of India 39 OOS-5 Inter-comparison of Wave Measurement by Accelerometer and GPS Buoy in Shallow Water off Cuddalore, East Coast of India Sisir K Patra and B K Jena National Institute of Ocean Technology, Chennai
The performances of Accelerometer and GPS buoy were tested off Cuddalore at 30 m water depth during 15 to 30 November 2010 by mooring the buoys 225 m apart from each other. Compared to other wave parameters, results of regression analysis on significant wave heights (Hs) shows a better correlation (correlation co-efficient R = 0.94) between Accelerometer and GPS buoy. A lesser co-efficient of R = 0.85 and 0.77 were resulted for wave direction and peak wave period (Tp) respectively. The waves were basically approaching from two directions, i.e. two wave forms or wave fields. One wave field was from around 80° and other was 140°. However, the wave directions averaged within each field over the observation period individually are in good agreement with both buoys. It was noticed that the predominant directions reported by these buoys were not identical always. Even though the buoys were placed at identical water depths (~ 30 m) and in close proximity (~ 225 m), they were reporting different predominant directions. The correlation seems low because it was determined to a large extent, with waves from different directions. Comparatively, zero up-crossing wave period (Tz) shows a better agreement with Tp, which may not be a robust parameter due to its dependence on estimation of spectral peak.
40 Ocean Society of India OSICON Proceedings 13-15 July 2011
ABSTRACTS
THEME-6 OCEAN REMOTE SENSING & APPLICATIONS
Ocean Society of India 41 ORSA-1 Validation of Satellite Derived Precipitation Data Abdulla C.P. and M.R. Ramesh Kumar Physical Oceanography Division, National Institute of Oceanography, Dona Paula, Goa
Recent progresses in remote sensing technology is very important in the hydrological studies. The Tropical Rainfall Measuring Mission (TRMM) is being flown by US and Japan to improve our quantitative knowledge of the 3-dimensional distribution of precipitation in the tropics. TRMM has a passive microwave radiometer, the first active space-borne Precipitation Radar (PR), and a Visible-Infrared Scanner (VIRS), plus other instruments. TRMM provides precipitation product at monthly to 3-hourly precipitation fields with 0.25x0.25 degree resolution. Global Precipitatin Climatology Project(GPCP) is another precipitation dataset available at one-degree resolution.The GPCP Data consists data from over 6,000 rain gauge stations, and also from geostationary and low-orbit infrared, passive microwave satellite data, and sounding observations have been merged to estimate monthly to daily precipitation fields. In the present study an attempt has been made to validate the satellite merged daily data product from TRMM and GPCP with a) Indian Daily Weather Report (IDWR) precipitation data for island stations (Aminidivi and Minicoy in Arabian sea, and Portblair and Carnicobar in Bay of Bengal) and b) RAMA buoy data for seven stations located in Indian Ocean. Analysis shows that TRMM has higher correlation than GPCP with both IDWR and RAMA datasets. From the time series plots of TRMM 3-hourly data and RAMA bouy 3-hourly data it was found that TRMM data can capture the diurnal variability of precipitation shown by RAMA data.
Key words: Satellite data, Validation, TRMM,GPCP.
42 Ocean Society of India OSICON Proceedings 13-15 July 2011
ORSA-2 Sea level and Eddy Kinetic Energy Variability in the Bay of Bengal from altimetry K.Palanik Kumar and P.P. Saheed* Institute of Remote Sensing Anna University, Chennai. *National Institute of Oceanography, Dona Paula, Goa.
The sea level and eddy kinetic energy variability of Bay of Bengal (BoB) at different time scales (monthly, seasonal and annual) over 17 years (1993-2009) was studied using satellite merged altimetry data (T/P+ERS1/2+Jason-1/2+EnviSat).
We find that the sea level rise in BoB is about 2.5 mm/year, which is within the averaged values of sea level rise for the global ocean (Xuhua et al, 2007, Ablain et al, 2009). The monthly mean sea level anomaly is maximum (9.8cm) in December 2008 and minimum (- 10.9cm) in January 1998. In 2008, the BoB experienced a number of intense cyclones and the year 1997-98 is characterised by an active El Nino event (Chen et al 2009, Chellappan et al 2009). SLAs (both positive and negative) during December of all the years (1993- 2009) show high fluctuations associated with warm and cold core eddies. The minimum SLA was observed in March/April. This annual cycle variation in sea level is due to the steric-effect - increase in the volume of ocean without change in the mass (Caballero et al., 2007). The intense variability in sea level along the east coast of India and around Sri- Lankan coast is due to the existence of western boundary currents (WBC).
The eddy kinetic energy (EKE), in turn, is found to be high during northeast monsoon (November-January) and southwest monsoon (June to September) seasons. During the non-monsoon period, EKE shows a weak positive trend. During the El Nino event (December 1997 to January 1998), the EKE is found to be high. High EKE during northeast monsoon season may be the reason for high SLA variability in the Bay of Bengal. Overall analysis shows that mean EKE ranges from a minimum value of 45.55 (cm2/s2) to a maximum value of 2780.6 (cm2/s2), with an average value of 461.5 (cm2/s2). According to Sharma et al (2010), instability in the monsoon currents, the Rossby wave propagation from the eastern BoB and wind stress curl are the main causes for the EKE variability in the BoB. We have further analysed SST and wind stress data to substantiate our study on the sea level and EKE variability in BoB.
Keywords: sea level anomaly, eddy kinetic energy, El-Nino, Rossby waves, Bay of Bengal
Ocean Society of India 43 ORSA-3 Potential Fishing Zone advisories- Are they beneficial to the coastal fisher folk? Kerala experience V.N.Pillai and Preetha.G.Nair CMFRI, Kochi -682018
Innovative validation of Potential Fishing Zone (PFZ) advisories generated by the Indian National Centre for Ocean Information Services (INCOIS) along Kerala coast during the period 2003-2011 revealed positive relationship between PFZ advisories and occurrence/ abundance of commercially important pelagic fishes such as Oil sardine, Indian mackerel, Anchovies, Carangids and Coastal Tunas. The usefulness of PFZ advisories, the only short term marine fishery forecast available in the country, for artisanal, motorized and mechanised sector fisherfolk towards obtaining comparatively higher catch per unit effort for the above mentioned major pelagics is proved beyond doubt through the results of more than 100 controlled experiments conducted onboard more or less identical commercial fishing vessels operating more or less identical fishing gear along Kerala coast.
Key words: Remote Sensing, Potential Fishing Zone, Validation, Oil sardine, Mackerel, Anchovies, Carangids, Coastal Tunas.
ORSA-4 Sea Surface Temperature estimation for condenser coolant discharges from a power plant using satellite data C. Anandan, R. Kaviyarasan, M. Sankar Ram, P.Sasidhar and V. Balasubramaniyan Safety Research Institute, Atomic Energy Regulatory Board, Kalpakkam – 603 102
Power plants are generally located on seacoasts owing to the ready availability of abundant seawater for condenser cooling. Condenser effluents from coastal power plants have the potential to impart thermal and chemical stress and, therefore, may pose environmental problems to the receiving water body. A study has been taken up on sea surface temperature (SST) studies by employing multi-dated satellite thermal infra-red imageries. The aim of the present study is to identify the temporal characteristics of the thermal plume signature around a coastal NPP site, Kalpakkam due to condenser coolant
44 Ocean Society of India OSICON Proceedings 13-15 July 2011 discharges using satellite derived Thermal Infra Red (TIR) image. The present work includes processing and conversion of Satellite data obtained from USGS website to derive Sea Surface Temperature (SST) by employing suitable algorithms. This SST map helps to plot thermal plume characteristics with respect to season. The study also includes validation of derived SST by comparing with field measured SST values.
ORSA-5 Upwelling in the southeastern Arabian Sea as evidenced by Ekman mass transport using wind observations from OCEANSAT–II Scatterometer Smitha, A., Ajith Joseph, K., Chiranjivi Jayaram* and A. N. Balchand** Nansen Environmental Research Centre (India), Kochi *Indian National Centre for Ocean Information Services, Hyderabad **Department of Physical Oceanography, Cochin University of Science & Technology, Kochi, India
Upwelling is an oceanographic phenomenon that involves wind-driven motion of dense, cooler, and usually nutrient-rich water towards the ocean surface, replacing the warmer, nutrient-deplete surface water and enhances biological productivity. In the presence of winds, often along coasts, the classical Ekman phenomenon occurs wherein, divergence or convergence in the Ekman layer causes upwelling or downwelling in the ocean. Negative values of the Ekman mass transport indicates an offshore movement of water and related upwelling. In this context, Arabian Sea is one of the highly productive seas in the Indian Ocean region where coastal upwelling occurs during summer monsoon (June– September) season. Off the southwestern coast of India, upwelling starts even before the onset of the summer monsoon and continues till it ends in September. In this paper we have estimated the monthly Ekman mass transport in the southeastern Arabian Sea using scatterometer data from Oceansat-II satellite. Level 3 daily wind data at 50kmx50km spatial resolution for the period from November 2009 to October 2010 has been used for the computation of Ekman mass transport. The intra seasonal variability of Ekman mass transport has been analysed to make an attempt to explore the dynamics behind the occurrence of coastal upwelling in this region. The prominent region of upwelling along the southwest coast of India has been identified between 8o and 14oN latitude.
The strongest offshore Ekman mass transport was observed during August due to the favourable wind conditions.
The maximum offshore Ekman transport of about -2000kg/m2/s was located off the southern tip of India. Very weak offshore Ekman transport was observed during the pre- monsoon months of March and April 2010 when the wind is weak and variable. Moderate
Ocean Society of India 45 offshore transport was observed along the southwest coast between December 2009 and February 2010. At the same time region off the southern tip of India and the open ocean west of 70oE experienced strong offshore transport. Besides, comparison of Oceansat-II scatterometer wind with ASCAT scatterometer wind has been carried out and it was found that they are in good agreement.
ORSA-6 Sources of Errors in the Measurements of Underwater Profiling Radiometer
Noah Silveira, T. Suresh, Madhubala Talaulikar, Bhushan Pednekar, S.G.Prabhu Matondkar, Aneesh Lotlikar* National Institute of Oceanography, Goa *Indian National Centre for Ocean Information and Services, Hyderabad, India
Surface optical parameters required for ocean color satellite applications need to be measured with high accuracy and errors within the permissible limits. These stringent requirements demand careful measurements of optical parameters. There are various sources of errors from the measurements of optical parameters using a radiometer, which can be classified as mode of deployment, instrument and environment. The errors from the deployment are primarily from the ship and superstructure shadows. The instrument could be a source of error arising from its self-shadow, drift in the calibration and temperature effects. There could be large errors, which at times may be unavoidable to environment factors such as wave focusing at the surface layers, sea state conditions which may affect the tilt of the instrument, atmospheric conditions such as cloud cover, solar elevation, wind and rain. The radiometric optical data in water could also get affected due to Raman scattering and fluorescence effects. Here we discuss the above sources of errors and how they could be minimized. From the measurements carried out in the coastal waters off Goa and Arabian Sea using the hype-spectral radiometer, we propose simple protocol to measure the data and also screen the erroneous data measured from the radiometer.
46 Ocean Society of India OSICON Proceedings 13-15 July 2011
ORSA-7 CHANGE DETECTION STUDIES OF RAMESWARAM ISLAND, INDIA USING REMOTE SENSING AND GIS
R.Gowthaman, G.S. Dwarakish*, V. Sanil Kumar and P. Vinayaraj National Institute of Oceanography, Dona Paula, Goa. *Department Applied Mechanics & Hydraulic, National Institute of Technology, Surathkal, Mangalore
Rameswaram Island, the geological formation of coral atoll with huge sand cover situated between India and Srilanka plays a vital role on the processes of exchange of littoral drift between the east and the west coast of India. Due to the Sri Lanka Island, the Palk Bay situated north of Rameswaram Island is sheltered and siltation is observed. The shoreline and land-use/land cover changes is studied using the Indian Remote sensing satellite (IRS-1C, IRS-P6) Linear Image Self-scan Sensor (LISS) III data during 1998 and 2008. The GIS technique is used to quantify the erosion and accretion. The base maps are scanned and registered using ERDAS image software and map composition is done using ArcGIS software.
A comparison between the Survey of India toposheet of 1969 and satellite data of 1998 indicates that during these years about 1.8 km2 erosion and 5.2 km2 accretion has occurred. During 1998 to 2008 erosion of 0.86 km2 and accretion of 1.7 km2 is found. The Land- use/land cover assessment based on visual interpretation during 1998 and 2008 indicates water body of 178 & 170 km2, sand features of 32 & 47 km2, vegetation of 29 & 26 km2 and coral reef of 5 and 10 km2 . The study shows that the sand spit along Dhanuskodi was growing.
Ocean Society of India 47 48 Ocean Society of India OSICON Proceedings 13-15 July 2011
ABSTRACTS
THEME-7 OCEAN STATE FORECASTING (OCEAN MODELING)
Ocean Society of India 49 OSF-1 Modeling of Coastal Inundation due to Storm Surges: A case study for Andhra Coast P L N Murty, A D Rao and S K Dube Centre for Atmospheric Sciences, Indian Institute of Technology Delhi
Numerical ocean models are as an essential tool to predict a spurt in the sea level rise over the region of cyclone landfall and the associated inland extent of flooding that could be generated along the coastal stretch. For this purpose an advanced two-dimensional depth-integrated (ADCIRC-2DDI) circulation model based on finite element formulation is applied for the Andhra coast to simulate storm surges and associated coastal inundation. Using the model, validation of surges and associated inundation generated by December 2003 cyclone which had landfall near the Machilipatnam coast is carried out. The simulations exhibit a good agreement with available observations from the post-storm survey reports. This region is known for its high vulnerability to cyclonic storms as it is being located in the low-lying area and its off-shore region is very shallow along the east coast of India. Hence, it is advocated that this region could be more prone to inland inundation from the produced surges. In the present experiment, a peak surge of about 2.0 meter is generated by the 2003 December cyclone. The model simulates the associated maximum inland inundation of about 4 km in the region. The surge dependence on the translation speed also has been investigated. Accordingly, it suggest that the peak surge tends to drop as the translation speed increases.
OSF-2 Numerical simulation and mechanism of mini-cold pool off the southern tip of India during summer monsoon season A D Rao and D K Mahapatra* Centre for Atmospheric Sciences, Indian Institute of Technology Delhi *National Centre for Medium Range Weather Forecasting (NCMRWF), NOIDA, Uttar Pradesh
Study of AVHRR5 SST data suggests that the mini-cold pool (MCP) off the southern tip of India (STI) and its intrusion into the south central Bay of Bengal (BoB) during the summer monsoon season is extended up to September in contrast to the earlier studies which suggests that it sustains till August. Numerical experiments are conducted to study and ascertain the mechanism associated with it. The mechanism that governs the occurrence of this MCP is not only due to upwelling caused by the divergence in the
50 Ocean Society of India OSICON Proceedings 13-15 July 2011 near-surface circulation off STI but also due to the advection of the cold water from the western Arabian Sea (AS) region and upwelled water from the southwest coast of India. This explains the extended cooling upto September at par with August. Moreover, the intra-seasonal and inter-annual variability of this MCP suggests that the driving mechanism for this is primarily the divergence of near surface circulation resulting in upwelling, advection and wind induced mixing. The cold water associated with MCP intrudes gradually into the south central BoB by the Summer Monsoon Current (SMC) right through September. The importance of the study lies in the fact that the formation and dissipation of MCP is related to the active/break phase of summer monsoon.
OSF-3 Numerical Hindcasting of Storm Waves during LAILA Cyclone using reanalyzed wind fields S.V.V. Arun Kumar, K.V.S.R. Prasad, K.V.K.R.K. Patnaik, Ch. Venkata Ramu, P.S.N. Acharyulu, D. Mani kumari and A.P.V. Apparao Andhra University, Visakhapatnam
The cyclonic storm Laila (means night in Arabic) is the first cyclonic storm to affect southeastern India in May 2010 since the 1990 Andhra Pradesh cyclone. It is the first severe tropical cyclone of the year 2010 that happened over North Indian ocean. Laila was developed on May 17 in the Bay of Bengal from a persistent area of convection and intensified as it tracked northwestward, became a severe cyclonic storm on May 19. The next day, it crossed south Andhra Pradesh coast near Bapatla in Andhra Pradesh between 1100 & 1200 UTC and weakened into a cyclonic storm at 1200 UTC close to Bapatla (Latitude 16.0º N & Longitude 80.5º E), and it later dissipated over north coastal Andhra Pradesh. It caused flooding and damage along its path. It is the worst storm to hit Andhra Pradesh over the last 14 years. Wave prediction is an important concept useful for naval, ship-routing and other offshore based industries. Waves are the immediate energy carriers that effect the coasts worsely during severe weather conditions and therefore very important to be predicted well in advance. There are several numerical models available for this purpose which needs predicted winds for forecasting the waves. The performance of the numerical model not only depends on the model elements but also on the accuracy and resolution of wind data. In this paper, we attempted to hindcast waves over Indian Ocean (30S to 30N and 30E to 120E) during the propagation of the severe cyclone LAILA using a Spectral wave Finite volume model. The 10-meter wind data was retrieved from ECMWF Interim re-analysis and NCEP/NCAR reanalysis for the study period. These wind fields were different in both spatial resolution as well as accuracy. The variation in wind
Ocean Society of India 51 wave, swell wave and other spectral characteristics are addressed at specific locations i.e., Chennai, Bapatla, Visakhapatnam and Paradeep stations in relation to the cyclone progression and development. The model is calibrated and the results are validated with buoy data from Pondicherry and Visakhapatnam. Statistical tools such as standard bias and RMS errors were applied for estimating the model performance. Results suggests that ECMWF reanalyzed wind data is giving better hindcast compared to NCEP data.
Keywords: Cyclone LAILA, wave hindcasting, MIKE 21 model, ECMWF and NCEP reanalysis.
OSF-4 Numerical simulation of cyclone movement using High Resolution Regional Ocean Model: A Case Study for the Cyclone Mala (24th - 29th April, 2006) Bishnu Kumar and Arun Chakraborty Indian Institute of Technology Kharagpur, Kharagpur, India
The prediction of cyclone track in the Bay of Bengal (BOB) is yet not lucid although it is a cyclone prone basin. This work presents the track of the severe cyclonic storm Mala (24th – 29th April, 2006) which was the strongest tropical cyclone struck over the BOB region. The Regional Ocean Modeling System (ROMS) has been setup for the BOB basin with 18 km × 18 km horizontal resolution and 32 vertical levels. The initial condition for the model simulation is derived from objective analysis (OA) field of the recent Real-time Geostrophic Oceanography (ARGO) and the Simple Ocean Data Assimilation (SODA) package (SODA v2.0.4) for 23rd April, 2006. The model is forced from 24th April, 2006 (starting date of the Mala) with the fields a) wind speed and wind stress components from QuikSAT, b) sea surface temperature (SST) from TRMM-TMI, c) air temperature at 2m, specific humidity at 2m, net surface heat flux and net surface shortwave radiation flux from WHOI OA flux data (version 3), d) air density and evaporation-precipitation are taken form Comprehensive Ocean-Atmosphere Data Set (COADS) and e) sea surface salinity (SSS), derived by OA field of the ARGO datasets and the SODA package.
The movements of the cyclone have been analyzed from the oceanic variables sea surface height anomaly (SSHA), cyclonic heat potential (CHP) and 26 °C isothermal depth (D26) from the model simulation. The model simulated currents show that two adjacent cyclonic eddies formed in 24th April, 2006 centered at 91° E; 15.5° N and 89.6° E; 9.0° N. This is favorable condition for depression as the eddies hold CHP of the order of 50 ×107 J/m2 and there are good correlations (> 0.9) of CHP with SSH and D26. In next day the southern
52 Ocean Society of India OSICON Proceedings 13-15 July 2011 eddy shifted to 89.4° E; 9.5° N to form deep depression as supported by the Indian Meteorological Department (IMD) (estimated at 90.5° E; 9.5° N). Then its center moved to the northeast and intensified into a cyclonic storm Mala in the next day with centre at 90.5° E 13° N (IMD estimated at 90.5° E; 12° N). In 28th April, a cooling of the sea surface of up to 1.3 °C is observed on the Mala track which is due to the mixing of the sub-surface 7 2 cold waters. There are also drop-off in CHP and D26 by 25 ×10 J/m and 22 m respectively from the initial day. In the next day Mala rapidly intensified at northeast to make it the first category 4 cyclone in the 21st century in the BOB basin.
Keywords: Cyclone, Mala, ROMS, CHP.
OSF-5 Indian Ocean Simulation Results from NEMO Global Ocean Model Imran M. Momin, Ashis K. Mitra, D. K. Mahapatra and L. Harenduprakash National Centre for Medium Range Weather Forecasting (NCMRWF), Noida
Nucleus for European Modeling of the Ocean (NEMO) is a state-of-the-art modeling framework for oceanographic research, operational oceanography, and coupled modeling for climate applications. NEMO system allows several ocean related components e.g. sea- ice, biochemistry, ocean dynamics, tracers etc to work either together or separately (Madec G., 2008). Recently a relatively newer version of NEMO (v_3.2) ocean model was configured in NCMRWF high performance computing system at a coarser resolution. For initial test purposes, the global model resolution was kept at approximately 2o x 2o latitude/longitude resolution to study the gross large-scale ocean circulation related features from the model simulations. In this simulation 31 vertical layers were used in the model. Out of these 20 layers were kept in the upper 500 meters of the ocean to take care of the tropical air-sea interaction realistically. The initial model conditions were prescribed from the climatological value. The model was integrated for 10 years with the monthly climatological data as forcing. The model-simulated parameters like surface currents, SST, SSS, D20 isotherm, heat content in upper 300mts were examined for different regions of the Indian Ocean. The simulations were compared against observed climatological data. In a broad sense the monthly, seasonal and the annual cycle patterns from the Indian Ocean regions match reasonably well with the observations. Results from the simulations will be presented in the conference. In near future, at NCMRWF NEMO along with the sea-ice model will be used at higher resolution for coupled modeling purpose for a variety of weather and climate related research studies.
Ocean Society of India 53 OSF-6 Time lagged Multiple Linear Regression Model Using Key Indices of SST Fluctuations for Smaller Domains of Oceans M. R. Anbarasan, S. Sundararajan*, B.K. Jena*, B. Vijay Bhaskar** and S. Chandrasekaran** Thiagarajar College, Madurai *National Institute Ocean Technology, Chennai **Madurai Kamaraj University, Madurai
Sea surface temperature (SST) or its derivative SST anomaly (SSTA) is a property of oceanic climate regime. The implied ecological significance SST variability had been widely accepted by scientific community. The correlation of SST variability to marine ecosystem responses such as bleaching events in coral reefs is an example of the significance. Many customized versions of models such as GCM (General Circulation Model) are currently in use today to explain the variability and dynamics of land-ocean atmospheric physical properties such as SST, wind, sea level and so on across larger domains. Many alternate models such as Linear Inverse Model (LIM) and Ensemble Forecasts (or Monte Carlo) were also frequently used. Here, we have explored the potential use of key indices of SST fluctuations in explaining the dynamics of SST in smaller domains. Patterns of SST fluctuations in the oceans were available as key indices such as North Atlantic Oscillations (NAO), Pacific Decadal Oscillations (PDO), Indian index (IND), South Atlantic Oscillations (SATL), and Nino 3.4. We have chosen thermal sensitive reef ecosystems as smaller domains in this study as a value addition. The reef domains included in this study were Belize islands (BEL), Pulley reefs (PUL), Andros island (AND), Red sea reefs (RED), Maldives (MAL), Gulf of Mannar (GOM), Raja Ampat (RAJ), Great Barrier Reefs (GBR) and New Caledonia (NEW). As we have found statistically significant linear trends in most of the smaller domains and the key indices, we have decided to use linear regression modeling as the tool to establish the relationships between the key indices and the SST variability in reef domains. Time lagged auto correlations and cross correlations by a positive ten years time lag among the key indices and reef domains were also seemed to exhibit statistically significant skill level for advance predictions. Since the trend and/or auto/cross correlations were insignificant, the key index Nino 3.4 and the reef RAJ were excluded from further analysis. So, by time-lagged multiple linear regression (MLR) analyses using XLSTAT Version 2011.1.01, we have factored in one or two key indices as independent variables along with the time-lagged SST variable of the reef domain of interest.
54 Ocean Society of India OSICON Proceedings 13-15 July 2011
By means of cross correlations and auto correlations at 95% confidence level, the reefs are grouped into three types of indices: (1) Indian, (2) PDO/NAO, and (3) SATL. These three groups also seemed to exhibit unique seasonal fluctuations. The model bias was validated using Mallow’s Cp coefficient which is one above the total number of explanatory variables used to fit the model. The mean square of errors (MSE) was slightly above the perfect accuracy and within the range of 0.100 to 0.324. The parameters were selected for model fitting using adjusted R squared method, which revealed high predictability of the models. The adjusted R squared values were within the range of 0.764 to 0.952. Further, forward forecasting were performed for ten years using the best fit models and SST anomalies were derived using 1971-’00 climatology. The back-casting and forecasting results were analyzed and the patterns were compared.
Key words: Multiple Linear Regression - SST fluctuations – Oscillation indices – Coral reefs
OSF-7 Wave forecast from wind parameters using Genetic Algorithm: A case study for the Bay of Bengal A D Rao, Mourani Sinha and Sujit Basu* Indian Institute of Technology Delhi, * Space Applications Centre, Ahmedabad
Basin scale prediction of ocean surface waves has major applications in various oceanographic fields. Generally such predictions are carried out using numerical models involving large computational resources. This work reports a new alternative technique for the prediction of significant wave height (SWH) field in the Bay of Bengal (BOB) region using a combination of empirical orthogonal function (EOF) analysis and genetic algorithm (GA). To begin with the WAM-4C model is integrated using NCEP blended winds from 2000 to 2008 (nine years) for the Indian Ocean covering 30ÚE to 120ÚE and 70ÚS to 30ÚN. The model computes daily SWH, wind speed (WS) and wind direction (WD) at six hourly intervals. In the present study the data is analyzed only for the BOB region covering 78ÚE to 103ÚE and 5ÚN to 25ÚN. Experiments are conducted using EOF and GA to predict SWH field using WS field, cosine of WD field (COSTHETA) and sine of WD field (SINTHETA). Initially the EOF analysis is performed separately on model generated SWH field, WS field, COSTHETA field and SINTHETA field for 8 years (2000-07). This is to decompose the space-time distributed data into spatial modes ranked by their temporal variances. Then we apply multivariate GA to the time series of the PC1 of the above four variables with lead times of 6, 12, 18 and 24 hours. We obtain the corresponding analytical forecast equations which are linear relations connecting SWH, WS, COSTHETA and
Ocean Society of India 55 SINTHETA. The data used for training the algorithm cover the period from 1st January 2000 to 31st December 2007 consisting of 11680 points. Independent data used for validating the algorithm covers the period from 1st January 2008 till 31st December 2008 consisting of 1460 points. For the independent data set we compute the PCs by taking scalar product of the corresponding data and EOFs of the training set. Then we use these actual PCs and the analytical forecast equation to obtain the genetically forecasted PCs. We then reconstruct the SWH of the independent set using the EOFs of the training set and the genetically forecasted PCs separately for 06, 12, 18 and 24 hours ahead. We calculate spatially distributed root mean square error between the actual and reconstructed SWH for all the lead times separately. Finally for any particular day, we compare model forecasted and GA forecasted SWH of 06, 12, 18 and 24 hours ahead. The method has the advantage that it can be used in the absence of any numerical wave model, since only past values of analyzed wind fields are required to predict SWH fields. The quality of forecast is evaluated in terms of root mean square error and found to be quite encouraging.
OSF-8 Simulations of tropical cyclone generated storm surges over the North Indian Ocean using advanced coastal hydrodynamic model
Maria Antonita. T, Remya P.G and Rajkumar Space Applications Centre, Ahmedabad
The estimation of tropical-cyclone-generated surges in the coastal region is of critical importance to the timely evacuation of coastal residents, and the assessment of damage to coastal property. Numerical modeling has become an essential tool for assessing the hydrodynamics of coastal waters and for the study of the complex coastal systems which aids in predicting storm surges and coastal inundations. In the present study, storm surge hindcast experiments were performed along the Indian coastal region using ADCIRC (ADvanced Multi-Dimensional CIRCulation Model for Shelves, Coasts and Estuaries), which is a depth integrated, finite element hydrodynamic circulation model. The hindcast simulations were conducted for the tropical cyclones occurred in both Bay of Bengal (BoB) and Arabian sea (AS). The model was forced with both atmospheric model and scatterometer derived winds along with tidal forcing. The results of the simulations performed i.e water elevation were validated with altimeter measured sea surface heights.
56 Ocean Society of India OSICON Proceedings 13-15 July 2011
OSF-9 Ocean Surface Forcing from AGCM: Medium Range Systematic Errors for Monsoons D. K. Mahapatra, A. K. Mitra, E. N. Rajagopal, Imran Ali and L. Harendu Prakash National Centre for Medium Range Weather Forecasting (NCMRWF), Noida
Surface forcing at air-sea interface plays an important role in driving the ocean circulation and distributing the water properties. In coupled systems, it plays an important role by contributing towards various feed-back processes, which modulates the processes in the atmosphere-ocean system. In numerical modeling, these forcing are usually taken from an atmosphere general circulation model (AGCM) or its analysis (assimilation system). It is therefore necessary to assess the representative ness and errors associated with these surface forcing parameters from the AGCM. Errors in first few days (medium range) are the most crucial, which dictates the subsequent errors in monthly, seasonal and climate scales. It is important to document and then diagnose these errors for further model development. In this study, an effort is made to quantify the systematic errors of surface forcing such as wind; sensible/latent heat fluxes; long/short wave radiations; rainfall and precipitable water for the North Indian Ocean region covering 30oS to 30oN and 30oE to 120oE during summer and winter monsoon of 2008-09 from NCMRWF T254L64 medium- range AGCM based weather forecasting system. The systematic errors are calculated with respect to model’s own analysis. For rainfall the daily observed TRMM data were used to compute model errors. From the errors it is found that the magnitudes are significant for the tropical region especially zones pertaining to coastal regions. The systematic errors generally increase with the forecast length. Contrasting error patterns are noticed for summer and winter monsoon periods. Results indicating these systematic errors will be presented in the conference.
Ocean Society of India 57 OSF-10 Assimilation of significant wave height from EnviSAT in coastal wave model using optimum interpolation at variable wave height ranges Suchandra A. Bhowmick, Raj Kumar and Sutapa Chaudhuri* Space Applications Centre, Ahmedabad, *University of Calcutta.
Ocean observations from the space based platform are extremely crucial for monitoring and prediction of ocean surface. Nadir looking, microwave radar altimeters are most commonly used for this purpose. Assimilation of the altimeter data in the ocean models are the frontline research areas related to improvement of the ocean state forecasts. In this study significant wave height (SWH) from EnviSAT radar altimeter data has been assimilated in the coastal ocean wave model SWAN (Simulating WAve Near-shore). The optimum interpolation (OI) technique has been used for this purpose. A detailed validation of the model and the EnviSAT observations has been carried out prior to the assimilation for the determination of the error covariance matrix of prediction and observation. The validation of the EnviSAT data and the model is done using the in-situ buoy observations and Jason-1 altimeter data.
The validation exercise revels that at various ranges of SWH the error covariance changes significantly for both the model and the altimeter measurements. The results shows that the assimilation of EnviSAT data at various ranges of SWH, using optimum interpolation scheme in SWAN model improves the prediction by 15 -20 % and there is reduction in the RMSE of SWH by 0.2 m. Multi-mission altimetric data assimilation using the same technique can improve the model prediction significantly.
OSF-11 Development of an automated Coupled Atmosphere- Ocean Modeling System and its Application for the Kalpakkam Region SubbaReddy Bonthu, Kaushik Sasmal, Hari.V.Warrior, Prageesh,. A. G Indian Institute of Technology, Kharagpur, India.
The present study reports on the development of an automated atmosphere-ocean coupling system to enhance the understanding of oceanic processes. The coupled system has the capability to simulate features such as ocean surface circulation, sea-surface
58 Ocean Society of India OSICON Proceedings 13-15 July 2011 temperature (SST) in a real-time mode. To accomplish this task, two state-of-art models viz; Weather Research & Forecast (WRF) Model developed at NCAR (National Centre for Atmospheric Research), USA and POM (Princeton Ocean Model) developed by the Princeton University, USA has been used. The model WRF and POM simulates the atmospheric and oceanic parameters respectively. These two state-of-art models are run in a real-time mode with exchange of physical parameterizations achieved through the coupling mechanism. The Flux coupling tool kit (FCTK) acts as an interface between these two models. Initially, the atmospheric model (WRF) is run utilizing FNL data (provided as initial and boundary condition) where the output produced from WRF is required for the subsequent POM run. The development of FCTK takes into account the estimation of momentum and heat fluxes from WRF, which is then provided as an external forcing parameter to POM in addition to climatology surface winds and the three dimensional temperature and salinity fields. In case with POM, the surface winds are obtained from Scatterometer measurements whereas the temperature and salinity fields at different levels are obtained from the World Ocean Atlas (WOA, 2009). Based on several synthetic experiments conducted and further establishing the robustness of FCTK, the developed flux coupler was applied for the Kalpakkam region located in the East Coast of India (about 70 Km south of Chennai) in the Tamil Nadu State. The location of Kalpakkam was chosen to study the dispersion characteristics of reactor plume outfall into the coastal waters of Bay of Bengal. Two different experiments were conducted for this study region (Kalpakkam coast) by forcing POM, firstly through momentum flux alone and secondly with the combination of momentum and heat flux through FCTK. It is expected that the second combination (combination of momentum and heat flux) should produce realistic simulations of SST and surface circulation, rather than using only the momentum flux. The trajectory of the plume and variability of SST in the immediate vicinity of outfall location show a good correlation with the SST measurements. Based on model runs, it could be advocated that inclusion of momentum and heat flux into POM through FCTK has the advantages to study reactor plume dispersion characteristics in a real-time mode.
OSF-12 Validation of Eddy Viscosity Model in the Laboratory Subhendu Maity and Hari V. Warrior Indian Institute of Technology Kharagpur
In this study an attempt has been made to experimentally validate a new eddy viscosity formulation. The new formulation is based on anisotropy unlike the two equation models which are very widely used but use a stability function approach which involves
Ocean Society of India 59 determination of complex form of stability functions. The new model is validated with experiments. The experiments are carried out in a recirculating water channel using an Acoustic Doppler Velocimeter(ADV) from Nortek AS, Norway one of the pioneers in making water velocity instruments. The instrument gives precisely the three velocity components in the laboratory at high sampling rate. The readings are taken in the turbulent flow regime created by placing a grid in a flow. The velocities obtained are then processed inside an associated post processor from Nortek, to give a measure of the turbulent stresses. These turbulent stresses help us to calculate the eddy viscosity using our formulation. The eddy viscosity calculated are then validated using the k − ε model first developed by Launder which had undergone successive modifications since then. The stability constant used in calculating eddy viscosity from k − ε model is taken as same as the one used widely for studying turbulent flow patterns in industrial flows. From the experiments carried out in the laboratory we found out that the eddy viscosity values we obtain are of the order 10-3 which are in tune with the values obtained from the two equation models viz. the k − ε model.
OSF-13 Indian Ocean Response to Windforcing using LCS Model M. Surendar Anna University, Chennai
Monsoons dominate the climate of the Indian Ocean and their neighbouring landmasses. Winds over the Indian Ocean blow from the Southwest during May-September and Northeast during November-February and drive a circulation that reverses its direction completely, which are dynamically important difference from the other tropical oceans. These monsoonal winds generate large seasonal variations in ocean currents, many of which display annual and semi-annual reversals.
The equatorial Indian Ocean, however, experiences a somewhat different seasonal wind forcing and hence has a different response than the other equatorial oceans. These wind forcing induced some disturbances on equatorial Indian Ocean, So due to Ekmen pumping Kelvin waves propagate towards east coast along the equator and Rossby waves propagate towards west coast along the north and south of equator. Kelvin waves after hitting the east coast splitted into north and south direction as a coastal trapped Kelvin waves. These coastal trapped Kelvin waves radiated Rossby waves towards west coast while moving along the south and north coast. According to the periodicity of input wind forcing the critical latitude of Rossby waves radiated by Kelvin waves varied. These large scale waves
60 Ocean Society of India OSICON Proceedings 13-15 July 2011 propagate over the entire Indian Ocean coast, and make influence to local currents combined with local wind forcing.
So understanding of local currents is not only depends on local wind forcing, which depends on remote forcing also. In this paper the brief study have been made for understanding the propagation of Kelvin waves and Rossby waves by various wind forcing and basin structure of Indian Ocean using LCS model. Various periodicity (50, 90&120) and steady input wind forcing in both zonal and meridional directions given as an input of Indian Ocean realistic basin, the behaviour of Kelvin and Rossby waves observed. Same experiments have made for both indian-srilanka palk opened and closed realistic basins, and the variations observed. QuikSCAT and ASCAT winds (daily averaged winds) validated using RAMA buoys data. The variation between QuikSCAT and ASCAT winds were observed, and how this variation impact the dynamics of Indian Ocean also observed. Finally observed the propagation of these waves during the cyclonic period.
These experiments clearly shown that the critical latitude of Rossby Waves radiated by Kelvin Waves has depended on input forcing periodicity. If periodicity high means critical latitude also high. According to periodicity of input forcing upwelling and downwelling Kelvin waves and Rossby waves generate and propagated.50, 90 and 120 day periodicity of input forcing excited the resonance periodicity. Finally observed the propagation of these waves during the cyclonic period.
OSF-14 Doubling of Tsunami Wave while at the Sea Shore: an Analytical Study Ramkrishna Datta Regional Meteorological Centre, Kolkata
Simple harmonic waves induced by Tsunami have been analyzed analytically. The velocity of propagation of waves depends upon the wave lengths. So the waves of nearly equal wave lengths can be considered as a group. This group of waves s will propagate with nearly equal velocity which is known as group velocity. On considering two consecutive simple harmonic waves of same amplitude, we can find two equations describing simple harmonic motions having slightly different wave lengths and time periods. The combination of these two said SHM’s we can find another resultant SHM with different amplitude than of the previous two SHM’s. This new SHM has a slight variation in wave length and time period than that of that of the said two SHMs. Then using the perturbation technique on this resultant equation of SHM we, can find a new wave velocity
Ocean Society of India 61 (group velocity) in differential notation of wave velocity. This differential notation of wave velocity has been eliminated from the relation between the wave velocity on the surface of water and the depth of the sea. Then we get a relation of group velocity with depth and wave velocity of the sea. The application of boundary conditions on depth of deep sea and that of the sea shore, we can find the group velocity at each region respectively. It is seen from the analysis that the group velocity at the sea shore is as much as double that of at the deep sea. Several recent cases of Tsunamis have been studied and it is found that the results depicted the same implementation that established by analytical study.
Keywords: Tsunami; Storm surge; Group Velocity; SHM; Hypo Centre; perturbation technique.
OSF-15 An implementation of Optimal Interpolation for wave height analysis over Indian waters N. Sasikala and S.A. Sannasiraj Indian Institute of Technology Madras, Chennai
In an operational environment, the need for high quality sea state data is constantly increasing. The significant wave heights in an area of increased interest, the Indian Waters are analysed based on buoy data and corresponding forecasts obtained from numerical WAve prediction Model (WAM). Until recently, wave observations were scarce in most parts of the world, so wave forecasting relied mostly on wave models forced by wind field from meteorological models. However they do suffer by its own inaccuracies due to their approximations and erroneous control variables. This provides a space for data assimilation schemes to stem where the available observations are introduced into the modeling procedures to have better predictions. In this study a widely used wave data assimilation technique called Optimal Interpolation scheme has been used. The essence of this methodology lies in the correction of the bias between wave model direct forecasts and buoy measurements. An error covariance structure has been formulated between the buoy observation at a discrete station and the numerical model prediction over the entire domain of interest. This is formulated to distribute the information inserted at one point over neighbouring points statically in a sequential mode, assuming that there exists a correlation between model predicted and buoy observed wave height. The differences to the conventional OI algorithm are filtering the negative correlations from the covariance structure to be consistent with the model physics and to accommodate the corrections from another observation station to avoid over prediction at any grid stations.
62 Ocean Society of India OSICON Proceedings 13-15 July 2011
The updated OI scheme has been implemented in Arabian Sea. The buoy data from DS1, DS2 and SW3 form the observation and validation stations. The updates over neighboring stations are discussed and the success of the OI scheme is highlighted. As expected, at the observation station, the analysed wave height has a good concurrence. At validation stations (DS2 and SW3), the assimilation proves an improved wave forecasts.
Keywords: WAM, Data assimilation, Optimal interpolation, Error covariance matrix
OSF-16 Wave Hindcasting using Artificial Neural Network with varying input Parameter J. Vimala and G. Latha National Institute of Ocean Technology, Chennai
The prediction of significant wave heights (Hs) is of immense importance in ocean and coastal engineering applications. The aim of this study is to predict significant wave height values at buoy locations with the lead time of 3,6,12 and 24 hours using past observations of wind and wave parameters applying Artificial Neural Network. Although there exists a number of wave height estimation models, they do not consider all causative factors without any approximation and consequently their results are general approximation of the overall dynamic behaviour. Since soft computing techniques are totally data driven, based on the duration of the data availability they can be used for prediction. In the National data buoy program of National institute of Ocean Technology, not all the buoys have wind sensors and wave sensors and so it is attempted to apply neural network algorithms for prediction of wave heights using wind speed only as the input and then using only wave height as the input. The measurements made by the data buoy at DS3 location in Arabian sea (12p 11’21"N and 90p 43’33"E) are considered, for the period 2003 - 2004. Out of this, the data of period Jan 2003-Dec 2003 was used for training and the data for the period July 2004- Nov 2004 is used for testing. MATLAB coding has been made for implementing ANN. In all the cases, TRAINLM was adopted as network training function. It is a network training function that updates weight and bias values according to Levenberg-Marquardt optimization. The transfer function used was logarithmic sigmoid, uniformly for first hidden and output nodes and purelin transfer function used for second hidden and output nodes. The performance of the models in significant wave height forecasting is evaluated using statistical measures, namely Root Mean Square Error (RMSE), Mean Absolute Error (MAE), and Correlation Coefficient (CC). The performance of ANN for varying inputs have been analysed and the results are discussed.
Ocean Society of India 63 OSF-17 Altimetry and drifter data assimilation in an Indian Ocean circulation model Manisha Santoki, K. N. Joshipura, Smitha Ratheesh*, Rashmi Sharma* and Sujit Basu* Sardar Patel University, Vallabh Vidyanagar 388 120 * Space Applications Centre, Ahmedabad 380 015
In the present work, we have assimilated two different types of surface data in a sigma coordinate Indian Ocean circulation model. The first data are of Lagrangian type and are the drifter derived currents. The second type is satellite altimeter derived sea level anomaly (SLA). The altimeter derived SLA has been assimilated sequentially using statistical— interpolation scheme, while currents from the drifter have been assimilated by nudging approach, in the spirit of an earlier study of similar nature conducted in the Gulf of Mexico (Lin et al., 2007). Thus the present study can be considered as a logical extension of the study by Ratheesh et al. (2011) in which only satellite altimetry data were assimilated. Several experiments have been conducted with and without altimetry and/or drifter data assimilation. For the purpose of comparison a forecast run (without assimilation of any data) has also been conducted. Impact of the assimilation has been quantified by comparing the model simulated variables like sea level and surface current against independent satellite and in situ observations. The standalone assimilations (either of drifter data or of altimetry data) show that the assimilations lead to an overall improvement in the quality of simulation. In the case of drifter assimilation there is deterioration in correlation for the sea level anomaly, which may be due to the fact that the model is attempting to simulate small-scale eddies not present in altimeter observations. As far as surface current speed is concerned, we conjecture that because of the paucity of the number of deployed drifters, the improvement is not very high and the situation may improve if more drifters are deployed. The standalone assimilation of SLA shows that there is largely positive impact. It is thus interesting to see whether the combined assimilation can further strengthen the hindcast capability of the model by enhancing the correlation between the simulated and observed variables and by reducing the associated root mean square errors.
64 Ocean Society of India OSICON Proceedings 13-15 July 2011
OSF-18 Tsunami Inundation Modelling and Mapping along Marina Beach, Chennai Using Cartosat-1 Data R. S. Kankara, S. Chenthamil Selvan*, Tune Usha and V. Ram Mohan* Integrated Coastal and Marine area Management Project Directorate, Chennai *University of Madras, Chennai – 600 025, India.
On 26th of December 2004 at 00:58:53, universal time (U.T.) an earthquake of surface wave magnitude (Mw) 9.0 occurred off the west coast of northern Sumatra. The documented death toll exceed-ed 283,000, with the heaviest loss along the west coast of Sumatra. Approximately 160 people died due to tsunami wave along the marina beach. In this paper, tsunami inundation modeling using was carried out using Cartosat data along marina beach. Marina beach, which is about 6 km stretch, is taken as the study area. CARTOSAT-1 is a state-of-the-art remote sensing satellite built by ISRO (Indian Space Research Organization).The satellite was launched by the PSLV on May 5, 2005 from the newly built second launch pad at Sriharikota, and is the eleventh satellite to be built in the Indian Remote Sensing (IRS) satellite series. In order to accurately predict the extent of inundation and run-up in the coastal areas, high precision topography data is required. Topographic data are, thus, a major input to a tsunami model for computing extent of inundation. The movement of tsunami wave on land is governed by the topography of that area. From Cartosat-1, Digital terrain model (DEM) can be extracted at 10m grid spacing. The numerical model “TUNAMI N2” used for this study is a nested grid model. Four grids, namely, A (2502m), B (834m), C (278m) in Linear mode and D (92m) in Non-linear mode are nested to form an inundation grid. Elevation datasets from CARTOSAT-1 and field measurement collected using Real time Kinematic GPS (RTK- GPS) were compared for these areas. In comparison, it was observed that in most point locations Cartosat data was much closer to the field collected RTKGPS data. RTKGPS field data has instrumental accuracy of less than 2cm. Based on the above comparison, it can be concluded that CARTOSAT, data points have an accuracy of +/-1.5 m with the RTKGPS. Extend of tsunami waves along the marina beach are collected from records for validating the result. The maximum inundation limit was 700 m from shoreline and the run-up of about 2-3m is observed in the area. Tsunami modeling was carried out using Cartosat and the inundation map was prepared at 1:1000 scales, which was very useful for coastal zone management.
Ocean Society of India 65 OSF-19 Sensitivity Study of Near-shore Wave induced Setup during an Extreme Event in the Bay of Bengal Prasad K. Bhaskaran and A.G. Prajeesh Indian Institute of Technology Kharagpur
Coastal flooding due to an abnormal increase in near-shore water level has profound implications in disaster preparedness and its mitigation. During extreme events an increase in water level is expected which can be due to cumulative effects arising from reduced sea- level pressure, storm surge, tidal effects and wave induced set-up. The present study deals on numerical investigation of the wave induced setup based on various sensitivity experiments, and application to a category-4 cyclone ‘NARGIS’ which developed in the central Bay of Bengal during April, 2008. Wave setup is an increase of water level in the surf zone arising due to the transfer of wave momentum to the water column during wave breaking process. During this process the wave energy is dissipated but not the wave momentum, which is thereby transferred to water column resulting in a slope of water surface to balance the onshore component of momentum flux. Firstly, the sensitivity experiments were performed for an arbitrary region having spatial dimensions of 5 Km ´ 5 Km with an open sea-ward boundary. Five different beach slopes viz; 1:80, 1:60, 1:40, 1:20 and 1:10 were assumed in this study domain, and for each of these slopes varying grid resolutions viz; 25 m, 50 m, 100 m, 250 m and 500 m were chosen for this numerical experiment. The wind speed was assumed as 20 ms-1 (taken at 10 m above water surface) blowing from offshore towards the coast. Forcing along the open boundary was accounted from JONSWAP spectrum corresponding to significant wave height of 9 m with a peak period of 12 s. Results from these experiments reveal that for gentle beach slope there is very marginal difference in significant wave height irrespective of model resolutions, unlike the case for a steep slope. Also the wave setup was found higher for a steep beach slope with fine grid resolution as compared to the coarse resolution grid. This attributes the fact that model resolution is not sensitive in estimation of wave setup for gentle sloping bottoms. Scaling down the grid resolution from 500 m to 25 m leads to wave setup which is about one order higher. In case of steep slope (1:10) computed wave setup with 500 m resolution is lower by 10% as that estimated with 25 m resolution. Based on results from these sensitivity experiments, wave setup calculations were performed near vicinity of Kalpakkam coast located in Tamil Nadu for the NARGIS cyclone event. Three locations were identified in the coastal belt having different beach slopes which being 1:80, 1:60 and 1:20. The nearest location of NARGIS from mainland was almost about 500 km away from open boundary of the study domain. The maximum computed significant wave height from SWAN model was 1.97 m with mean periods of 8.5 s. The computed wave setup was found highest for the steep slope (1:20) which being 0.3 m. This study advocates that wave setup is an important parameter which essentially needs to be included in an operational storm surge forecasting system.
66 Ocean Society of India OSICON Proceedings 13-15 July 2011
ABSTRACTS
THEME-8 OCEAN DYNAMICS
Ocean Society of India 67 OD-1 Barrier Layer Formation in the Bay of Bengal as observed by Omni Buoys during Northeast Monsoon Simi Mathew, G. Latha and R. Venkatesan National Institute of Ocean Technology, Chennai
The freshening of surface layers of the Bay of Bengal (BoB) with the river discharges during southwest monsoon (SWM) and its course through the east coast of India with the East India Coastal Current (EICC) during northeast monsoon (NEM) plays a major role in bringing low saline waters into the south. The salinity profiles at the OMNI (Ocean Moored Network for Indian Monsoon) buoy location during NEM reveal a subsurface maximum in conjunction with the strong southwest currents. This favours the formation of strong barrier layer in the southern BoB during NEM. The presence of high saline water mass in the subsurface level in central BoB during SWM period was explained by the Arabian Sea high saline waters. But the presence of this subsurface high saline water even during NEM period traces its origin to the northern BoB. The close examination of subsurface currents reveals close correlation between subsurface southwest currents and high saline waters. This is a proof for the fact that lowering of salinity in the northern BoB by river discharges is limited to the upper layer (0-50m) of water column.
The Arabian Sea and BoB even though lies in the same latitudinal belt due to high evaporation rate of Arabian Sea waters over BoB and high river discharges into the BoB it was found that Arabian Sea waters are high saline compared to BoB. The two OMNI buoys [BD13 and BD14] deployed in the southern BoB gave continuous data for salinity, temperature and current up to subsurface levels during the NEM of 2010. The winds during NEM favour the formation of EICC along the east coast of India. The bifurcation of EICC to the east at the southern tip of Sri Lanka brings in low surface saline waters to the buoy location. The low saline waters are associated with strong north east currents and the geostrophic currents during this period obtained from sea surface height obtained from AVISO satellite clearly shows this low saline water as a wing of EICC. There is not much study of the subsurface salinity distribution in the BoB during NEM period. The salinity profiles obtained from both the buoy locations shows the presence of subsurface high salinity associated with strong southwest currents. This clearly shows the origin of these subsurface maximum saline waters to the northern BoB. The river discharges can only affect the upper water column 0-50m depth. The high saline waters are confined to 50-100m depth in the northern BoB. Earlier studies conducted during SWM period also shown the presence of high saline waters in the south central BoB and since the currents were northeast during this period this high saline waters were originated from Arabian Sea high saline waters.
68 Ocean Society of India OSICON Proceedings 13-15 July 2011
OD-2 Spatial and Temporal Variation of Heat Content in the Upper 70m layer of the Arabian Sea Gopika. N and Sajeev. R Cochin University of Science and Technology, Kochi – 22, Kerala, India
The upper ocean heat content is the most important parameter in view of ocean atmosphere interaction processes. In this study the temporal and spatial variation of heat content in the upper 70m layer of the Arabian Sea for a period of 1991 to 2008 have been attempted. Sea Surface Temperature (SST) and Net Heat Flux (NHF) are the two major factors that affect the heat content of the ocean. In order to establish the various role played by these two factors on the upper ocean heat content we have explained the spatial and temporal variation of NHF and SST in the Arabian Sea. The investigation was carried out in three selected basin-wide boxes in the Arabian Sea; Box1 (Western Arabian Sea-8oN-20oN &50oE- 60oE); Box 2 (Central Arabian Sea-8oN-20oN &60oE-70o E) and Box 3 (Eastern Arabian Sea- 8oN-20oN &70oE-80oE). The inter-annual variation of heat content, NHF and SST in these three boxes during pre-monsoon, summer monsoon and winter monsoon seasons have been analyzed. Vertical profiles of temperature from the assimilated model output of SODA is used to calculate the upper ocean heat content and the NHF data was taken from OAFlux data sets. Eastern Arabian Sea experienced a large amount of heat content and it decreased towards western region. Inter annual variation of heat content showed that during the strong IOD and strong El-Nino years (1997-1998, 2002-2003 and 2006- 2007) all the three regions exhibited maximum heat content. In the western and eastern Arabian Sea, maximum heat content was observed during the pre-monsoon season and minimum heat content was observed during the summer monsoon season. But central Arabian Sea experienced maximum heat content during the summer monsoon season and minimum heat content during the winter monsoon season. From the analysis of SST and NHF we conclude that in the western Arabian Sea, SST is the main factor that affects the heat content but in the eastern and central Arabian Sea both SST and net surface heat flux played a major role in influencing the heat content.
Ocean Society of India 69 OD-3 Influence of Indian Ocean Dipole(IOD) on Northeast Monsoon
K.N.Navaneeth and M.R.Ramesh Kumar Physical Oceanography Division, NIO, Donapaula,Goa-403004. e-mail: [email protected]
Most parts of the Indian subcontinent receives over 75-90% of mean annual rainfall during South-West Monsoon.The Southeast peninsular India which falls under the rainshadow region during Summer Monsoon due to the presence of Western Ghats receives a good amount of rainfall during Northeast Monsoon.The large scale South-West Monsoon associated with well developed Synoptic features has been well studied whereas Northeast Monsoon over Southern peninsular India receives less attention.This study focusses on North East Monsoon Rainfall[NEMR] variability for a 48 year period and its relationship with Air-sea fluxes and SST,using Objectively Analysed flux data[OA-FLUX].Air-sea fluxes like Latent heat,sensible heat,Evaporation,Wind and SST over the entire Indian Ocean has been correlated with NEMR variability.It has been observed that SST in the Eastern Equatorial Indian Ocean[0-10S,90E-110E] shows a positive correlation[0.4-0.5] in the months of October and November.This region falls under the Eastern mode of Indian Ocean Dipole[IOD].Hence the influence of IOD on Northeast monsoon is studied.The northeast monsoon and IOD are directly linked,suggesting that positive phase of IOD enhances Northeast monsoon while the negative phase suppresses the Northeast monsoon.The influence of IOD on Northeast monsoon is studied using National Centers for Environmental Prediction-National Center for Atmospheric Research reanalysis data(NCEP-NCAR).The wind pattern associated with the positive phase suggests a transfer of moisture from eastern Indian Ocean towards southern peninsular India.However the wind pattern associated with the negative phase of the mode suggests moisture transport away from the southern parts of India.Thus positive phase of the mode supports the transport of moisture towards India enhancing rainfall activity and negative phase inhibits the transport of moisture towards India suppressing rainfall activity.This clearly demonstrates the coupled Ocean-Atmosphere interaction in the tropical Indian Ocean.
Key words: Northeast Monsoon,Air-sea fluxes,NEMR,Indian Ocean, IOD, NCEP-NCAR
70 Ocean Society of India OSICON Proceedings 13-15 July 2011
OD-4 Influence of IOD events on sea surface height variability and circulation characteristics along the South - West Coast of India Phiros Shah and Sajeev R. Cochin University of Science and Technology, Kochi-22, Kerala, India.
Sea surface height variability over the south-west coast of India were studied for a period of eight years from 1993-2000 using all the available satellite measurements. The period includes two significant negative and positive IOD years. The study mainly focused on the influence of remote forcings on the downwelling phenomenon and its temporal variability. It was observed that during the positive IOD years the significance of downwelling Kelvin waves were absent along this coast. But normal and negative IOD years showed well defined patterns of coastally confined wave characteristics. During the negative IOD years there are significant changes happened in winter season in terms of coastally trapped wave propagation, when compared to the positive IOD years. In the month of October of the negative IOD years 1996 and 1998, Sea Surface Height Anomaly (SSHA) all over the South Eastern Arabian Sea (SEAS) is lower as compared to positive IOD years. But in December there was a rapid increase in SSHA during negative IOD years along the coastal region. Compared to the normal and negative IOD years, strength of the coastal currents seems to be diminished along the coast in the positive IOD years. This highlights that the strength of pole ward coastal currents are enhanced by the propagation of downwelling Kelvin waves.
OD-5 Water Mass Characteristics of the Andaman Sea Sudip Jana and Arun Chakraborty Indian Institute of Technology, Kharagpur, Kharagpur - 721302, INDIA
The Andaman Sea (AS), a very less studied area of the Indian Ocean is located along the southeastern side of the Bay of Bengal (BOB) and bounded by the Malay Peninsula in the east, Irrawaddy Delta in Burma in the north, Sumatra in the south and the Andaman and Nicobar islands in the west. After few meters of depth, it is surrounded by land from all the sides and it behaves like trench. The rapid change in depth gives a special effect in its bathymetry. The northern and the eastern parts are shallow whereas the western side is with steep slope and the depth suddenly changes to greater than 4000 meter in the centre
Ocean Society of India 71 of the Sea. Andaman and Nicobar islands behaves like a wall separating the AS from the remaining part of the BOB. The AS exchanges its water mass with the BOB through the three main channels: Preparis Channel, the Ten Degree Channel and the Great Channel. In the southern side it is connected to the Malacca Strait, which allows the exchange of the subsurface water mass with the Indonesian Seas. This special effect of the bathymetry makes its deeper water mass isolated from the remaining part of the Bay of Bengal. This study presents a brief analysis of the water mass characteristics of the Andaman Sea and its seasonal variation. Historical in-situ Conductivity-Temperature-Depth (CTD) data, Profiling Float (PFL) data and Ocean Station Data (OSD) from the World Ocean Database (WOD09) have been used in this study. Analysis has been done to identify the pattern of water masses in the Sea. The physical properties we have analyzed are the temperature and the salinity over the years. Comparison has been done between the water masses from the AS and its surrounding regions (i.e. the western side of the Andaman and Nicobar Islands). The results indicate the existence of relatively warm and high saline water in the deeper part of the sea and low saline water in the subsurface region in comparison to the surroundings of the sea. The water mass of AS basin is greatly influenced by the transport of monsoon currents and Malacca Starit throughflow.
OD-6 Seasonal cycles of heat budget components during the contrasting years of 2004 and 2007 P.M.Muraleedharan, Keerthi, M.G., *Nisha, P.G. National Institute of Oceangraphy, Goa 403004. *Indian Institute of Science, Bangalore-560 012
Sea Surface Temperature (SST) and Wind Speed (WS) data over the tropical Indian Ocean during the contrasting years 2004 and 2007 were derived from the ascending and descending passes of TRMM (Tropical Rainfall Measuring Mission) Microwave Imager (TMI) and humidity from SSMI brightness temperature data following Schlussel et al. (1995). The latent (LHF) and sensible heat (SHF) fluxes were computed from the above parameters using COARE 3.0 algorithm proposed by Fairall et al., (2003). The net oceanic heat gain was then calculated from the above parameters. Quality checked monthly averaged Argo profiles together with CTD profiles [World Ocean Data Center (WODC) and Indian National Oceanographic Data Center (INODC)] leaves less gaps to be filled with interpolated (krigging) values to have sufficient temporal and spatial coverage over the tropical Indian Ocean in 2004. The horizontally interpolated (variational analysis interpolation technique) and gridded monthly data products were obtained for the year
72 Ocean Society of India OSICON Proceedings 13-15 July 2011
2007 from the IPRC (International Pacific Research Center) web site (http:// apdrc.soest.hawaii.edu/datadoc/argo_iprc.php). The zonally averaged oceanic heat content with in the mixed layer, heat storage, heat export and heat transport were then computed during both years to understand the inter annual variability. The area multiplied monthly net oceanic heat flux, heat storage and heat transport were then integrated from north to the equator to make the comparison easy and meaningful.
Anomolous solar heating and enhanced surface wind situation weakens the air-sea coupling process in 2007 whereas the relatively low SST and weak wind in 2004 generated high LHF as a result of enhanced air-sea coupling. The seasonal cycles of both heat storage and heat export pattern indicated southward propagation during the monsoon months of 2004 and 2007 and are supported by the heat transport computations incorporating both geostrophic and ekman components. Heat depletion of the north Indian Ocean during summer months is much higher in 2004 compared to 2007. The enhanced meridional heat transport of 2004 is responsible for such depletion. Similarly weak meridional transport may be responsible for the low heat depletion noticed in 2007.
The anomalous heating of the ocean makes the surface layer more stratified and slow down the meridional overturning cell resulting in dampened meridional transport. The surface stratification, as in the case of the year 2007, retains the SST above the prescribed threshold of 28 C thereby creating situation conducive for triggering atmospheric disturbances. In the year 2007 there were about 26 low pressure systems developed in the north Indian Ocean when compared to 12 such systems in 2004. This feed back from the ocean along with LaNina induced Walker circulation probably supported the enhanced rainfall over the subcontinent and marked 2007 as a normal monsoon year and the year 2004 was declared as a draught year due to the subsidence caused by ElNino although the evaporation was highest in 2004.
Key words: Meridional circulation, heat storage, heat transport, Indian Ocean, air sea coupling, Argo profiles.
Ocean Society of India 73 OD-7 Sea breeze induced wind sea generation and growth in the central west coast of India during pre-monsoon season V.M. Aboobacker, P. Vethamony, M. Seemanth National Institute of Oceanography (CSIR), Goa
It was identified that the wind seas generated due to sea breeze superimpose with pre- existing swells off Goa during pre-monsoon season and creates complex sea states. The associated characteristics are increase in wave height and decrease in mean wave period. However, it is essential to understand the generation and growth of sea breeze induced wind seas and their interaction with pre-existing swells, which is not yet fully understood. One of the limitations in studying the interaction is the lack of fine resolution winds, which could be applied as the input parameter in numerical wave modelling. Global winds such as NCEP (National Centers for Environmental Prediction, USA) and ECMWF (European Centre for Medium-range Weather Forecasts) have limitations in its temporal and spatial resolutions as well as in representing the winds very close to the coast. In the present study, a mesoscale model, MM5 has been implemented to simulate winds off Goa during pre-monsoon season which is capable of reproducing fine details of sea breeze characteristics. These model winds are validated with winds measured using Autonomous Weather Station (AWS) on the Goa coast. Spatio-temporal variations in the wind velocities over the sea breeze dominated area have been traced. Waves measured off Goa clearly showed the presence of sea breeze induced wind seas, and the wind sea parameters have been separated from the wave spectra.
Numerical wave model has been set up to simulate wind seas off Goa during pre-monsoon season utilising MM5 winds, and the wave model results have been validated with measured wind seas. The correlation coefficient, bias, r.m.s.error and scatter index between measured and modelled significant wave heights are 0.73, 0.03 m, 0.12 m and 0.26, respectively. This shows that MM5 winds reproduced the wind seas off Goa more accurately than previous efforts, in which NCEP winds were used as the input parameter. It has been found that the wind seas due to sea breeze are generated at an offshore area between 100 and 150 km away from the coast, and a gradual wind sea growth towards the coast is evident as the sea breeze intensifies.
74 Ocean Society of India OSICON Proceedings 13-15 July 2011
OD-8 The role of Thermal inversions on Hydro-physical processes along the coastal waters off Visakhapatnam, East coast of India T. Sridevi, K.Maneesha and V.V.S.S. Sarma National Institute of Oceanography, CSIR, Visakhapatnam – 530017, India
Thermal inversions are one of the important physical processes seen most commonly in the Bay of Bengal. In this work, we focused on the formation of thermal inversions in the very shallow coastal waters off Visakhapatnam, as this affects the coastal upwelling, nutrient input and therefore primary productivity. We have conducted monthly survey in the coastal BOB, off Visakhapatnam, from 10m depth to 100m depth water column from October 2007 to February 2010 to understand the effect of inversions on coastal processes and causative factors responsible for very shallow waters. We also addressed the influence of remote forcing in the modulation of temperature inversions in this region. Based on the observed data we classified these inversions into two types - salinity driven thermal inversions and temperature driven thermal inversion. Due to weakening of EICC during January, February the fresh water influence on surface decreases. The thermal inversion of 0.26°C to 1.2°C where observed during winter in the coastal BOB when relatively weak stratification compared to monsoon period was observed due to weakening of EICC. During winter atmospheric temperature decreases by 5°C. During this period inversions were observed up to 70-80m. The weak thermal inversion during summer was associated this strong stratification resulting in decrease of vertical mixing. Therefore inversion during winter and summer caused atmospheric temperature and salinity by river discharge respectively. The magnitude of inversions decreased towards offshore and deepened from coast to offshore. It was observed that low nutrients and chlorophyll- a concentration where associated thermal inversions suggesting that inversion plays significant role of marine ecosystem in the costal BOB.
Ocean Society of India 75 OD-9 Variability of near-surface temperature fields on Intra-seasonal to inter-annual time scales in the south eastern Arabian Sea (SEAS) Nisha Kurian1, V.V.Gopalakrishna1, R.R.Rao2, S.Amritash3, Lix John3 and C.Revichandran3 1 National Institute of Oceanography, Dona Paula, Goa -403004, India 2Andhra University, Visakhapatnam - 530003, India 3National Institute of Oceanography Regional Centre, Kochi-682018, India
South eastern Arabian Sea (SEAS) located in the northern Indian Ocean is an important region on many counts. For example, core of the Indian Ocean warm pool forms over this region whose strength determines the onset and northward extension of the Indian summer monsoon season. SEAS is one of the most biologically productive regions of the world oceans contributing to large fishery resources due to upwelling during Indian summer monsoon season (SMS). During winter, advection of Bay of Bengal origin low salinity and low temperature waters in to SEAS significantly reduces the salinities over this region and leads to the formation of barrier layer which ultimately supports formation temperature inversions. It is believed that these temperature inversions enhances the SST and helps strengthening the warm pool. Thus plays a key role in the regional climate system. However due to paucity of systematic short term (weekly to fortnightly) temperature/salinity measurements for longer periods following are not well known: the interannual and intra-seasonal variability of (a) salinity and its contribution on the evolution of temperature inversions and its characteristics, (b) upwelling and (c) upper ocean thermal structure.
Under the Ministry of Earth Sciences (MoES), Government of India supported long term observational program, we have been collecting vertical temperature profiles by deploying expendable Bathy Thermographs (XBTs) and water samples for the analysis of sea surface salinity (SSS). The data are collected since 2002 onwards at fortnightly time and 50km spatial intervals in the SEAS using ships of opportunity. Utilizing the unique eight years temperature / salinity data and supporting with satellite measurements (surface winds, OLR, TMI SST, AVISO girded SSH) we tried to answer the above posed questions in the present study.
76 Ocean Society of India OSICON Proceedings 13-15 July 2011
OD-10 Influence of mesoscale eddy on vertical mixing and spreading of water mass in the Arabian Sea PA Maheswaran, Dominic Ricky Fernandez, J. Swain Naval Physical and Oceanographic Laboratory, Cochin
Variability of surface circulation and water mass in southern Arabian Sea extending from Somali coast to the west coast of India have been studied using data sets from multimission Altimetry, Tropical Rain Measuring Mission (TRMM) satellite’s SST and hydrographic temperature and salinity. In winter, the cyclonic eddy off Somali coast prevents the westward spreading of low saline waters brought by the North Equatorial Current, consequently this low saline waters re-circulate in the south-eastern Arabian Sea. In order to examine the influence of mesoscale eddy on the vertical mixing and spreading of watermass, potential vorticity and cyclonic eddy index were calculated. It was found that, characteristics of the Arabian Sea mini warm pool significantly depend on the winter time mesoscale eddy index. Further, a quantitative study of mixing and subduction of water masses viz., Bay of Bengal, Arabian Sea, Somali and Equatorial surface waters were also investigated for the west, central and eastern portions of study region.
Key words: Mesoscale eddy, watermass, Arabian Sea mini Warm pool, cyclonic eddy index, potential vorticity.
OD-11 Characteristics of Bay of Bengal Water mass in the South Eastern Arabian Sea during 2001-2002 G Nageswara Rao, K Anil Kumar, PSV Jagadeesh and P Anand Naval Physical and Oceanographic Laboratory, Kochi
The low saline Bay of Bengal water intrusion to the Arabian Sea along the west coast of India during the north east monsoon is a well known fact. This paper examines the characteristics of this intruded Bay of Bengal water mass (BBW) during November 2001 – May 2002 by utilizing Simple Ocean Data Assimilation (SODA) model outputs (T, S and Currents). During November 2001 the southward flowing East India Coastal Current (EICC) along with the Winter Monsoon Current (WMC) brings BBW to Arabian Sea traversing around Sri Lanka coast and feeds the poleward flowing West India Coastal Current (WICC). Even though EICC reversed its direction by January, the WMC along with the WICC transported the BBW further north. The maximum northward limit of the
Ocean Society of India 77 BBW was 15.25°N during January-March which is peak phase of WICC. When the WICC reversed its direction by March the BBW started depleting and by May no trace of BBW was seen in SEAS. Further, the thickness of the water mass were computed for the entire study region and also vertical integrated volume transport were computed along transects (77.5°E,8.25°N,10.25°N,12.75°N and 15.25°N) perpendicular to the coast. The thickness of the water mass was found to vary from 10 to 50m during the entire study period. It was shoaled during the November and March-April while it deepened during peak phase of WICC (January-February). Maximum volume transport of 0.8 Sv towards west along 77.5°E was observed during February. During all months total volume transport was seen to be reducing towards the Northern transects.
OD-12 Air-sea interactions and upper ocean thermal structure variations during different epochs of MALA Cyclone over Bay of Bengal Naresh Krishna Vissa, A.N.V. Satyanarayana, and B. Prasad Kumar Indian Institute of Technology Kharagpur
Tropical cyclones are one of the major natural hazards which inflict severe threat to human life and property having implications on socio-economic aspects in the affected regions. It is considered as the most intense case in air-sea interaction studies where energy from the warm ocean waters is supplied through surface heat flux. ARGO profiling floats provides valuable information of the ocean’s temperature and salinity structure even during the passage of cyclones. Temperature and salinity profiles for the present study were obtained from eleven different ARGO floats for the period 14 April to 9 May 2006 (±10 day’s window of MALA passage) in the study domain encompassing geographical coordinates bounded by latitude 5-20oN and longitude 85-95oE within the vicinity of MALA cyclone track which was formed and dissipated during 24-26 April 2006 over Bay of Bengal. The passage of MALA cyclone also resulted in cooling the sea surface temperature (SST) by 4-5°C. The findings suggest that turbulent and diapycnal mixing are responsible for cooler SSTs. A significant variation of mixed layer depth (MLD) and barrier layer thickness (BLT) during the different phases of MALA is noticed. Deepening of MLD and weakening BLT associated with a deeper 26° C isotherm level (D26) is observed after the MALA T passage. Tropical cyclone heat potential (TCHP) and depth averaged temperature ( 100 ) exhibit good degree of correlation for higher values. Turbulent air-sea fluxes are analyzed using Objectively Analyzed air-sea Fluxes (OAFlux) daily products. During the mature stage of MALA higher fluxes of sensible and latent heat and enthalpy are observed in the right side of the track of this extreme event.
Keywords: Upper Ocean, mixed layer, TCHP, air-sea fluxes
78 Ocean Society of India OSICON Proceedings 13-15 July 2011
OD-13 Implication of Empirical Orthogonal Function Analysis to Objectively Analyzed Ocean Temperature Data of Bay of Bengal Tarumay Ghoshal, Sudip Jana and Arun Chakraborty Indian Institute of Technology Kharagpur, Kharagpur-721302, India
Empirical Orthogonal Function analysis is a very powerful statistical technique which decomposes multivariate dataset into some orthogonal basis functions, called modes which include both temporal and spatial patterns. This method can reflect to some essential signal characteristics from the larger dataset. The objective of this study has been divided into two categories. First, to obtain the intrinsic and valuable informations from the ocean temperature data for the Bay of Bengal through empirical orthogonal functions. Second, to reconstruct the whole dataset from the dominant modes and comparison with the original data to show the accuracy. It is well known that Bay of Bengal temperature is influenced by several factors like monsoon effect, enormous river discharges and dominant ocean current systems. Due to lack of availability of proper in-situ data, it was quite difficult task to interpret the proper variations of ocean temperature for a long time. After the availability of ARGO floats data that task has become comparatively easier. In the present study we have used the climatological temperature data over the Bay of Bengal obtained from the assimilation of the recent ARGO observations into the 0.25° Levitus climatology by objective analysis. Empirical orthogonal function analysis is accomplished on this new dataset through singular value decomposition method. The method is done in two steps. First, the temporal mean is removed from the data set and then decomposition is done. Next, the process is repeated after removing the spatial mean from the original dataset. The decomposition generated temporal and spatial modes for both the steps, and which are analyzed thoroughly. Taking five dominant modes, the whole dataset have been reconstructed. The accuracy of this computation is calculated through skill analysis. Temporal mode time series shows high correlation with the spatial mode patterns for the near surface temperature. Specially, mode three reveals temperature variations almost according to Indian Ocean dipole index and ENSO index. This is also evident from spatial mode patterns. The seasonal dominance of high sea surface temperature near the Ganges- Mahanadi river discharge is very much proved from the spatial mode patterns. From the comparison between original dataset and the reconstructed dataset, it is revealed that empirical orthogonal function analysis not only extracts the small intrinsic signals, but also acts like a smoothing technique which filters out the unwanted signals. Skill analysis reveals accuracy in the range of 98-99%.
Ocean Society of India 79 OD-14 Dynamics of intraseasonal thermocline variability in the Tropical Indian Ocean during 2004 Bhasha M. Mankad, Rashmi Sharma, Sujit Basu and P. K. Pal Space Applications Centre, Ahmedabad 380 015
For the tropical Indian Ocean, depth of the 20o C isotherm (D20) is a reasonable proxy for the thermocline depth. An ocean general circulation model (OGCM) is an important diagnostic tool to study the upper ocean variability, including the variability of D20. In the present study, Modular Ocean Model, version 3.0 (MOM3.0) has been used to study the intraseasonal variability of D20. Two runs of the model have been performed for the year 2004. In the first run , hereafter designated as Reference Run, the model is forced with daily fluxes from NCEP reanalysis and winds from QuikSCAT for the year 2004 (CNTL-R). In the second run, designated as experimental run (EXP-R), weekly MSLA data are assimilated in the model, while retaining the same forcings. The MSLA data are assimilated through the water property conservation scheme. The validation of the runs is done at few locations using data from RAMA buoys.
In order to study the dynamics of thermocline variability, spectral analysis of the time series of D20 at few buoy locations were carried out. Dominant spectral peaks in the intraseasonal frequencies are analysed in detail. Further runs of the model are performed after removing the intraseasonal oscillations and a diagnosis of the causes affecting variabilities at different time scales are analyzed.
OD-15 Effect of Sea ice melting on the mixed layer depth variation in the Indian Ocean Sector of the Southern Ocean Pranab Deb, Mihir K. Dash and P. C. Pandey Indian Institute of Technology Kharagpur, Kharagpur-721302
Melting of sea ice in different sectors of the Antarctic modifies the regional mixed layer properties of the ocean as well as has a remote effect. This study describes the effect of sea ice melting on the changes in the mixed layer depth in the Indian Ocean sector of the Southern Ocean. The temperature and the salinity profiles from the World Ocean Database 2009 Geographically Sorted Data (WOD09) for the region 50oS-60oS and 60oE-90oE from 1978 to 2007 have been used to study the mixed layer depth (MLD) characteristics of the region. The thermal mixed layer, density mixed layer and the barrier layer were calculated from the individual profiles for the months of January and February. Then monthly averages were computed for January and February. The average values were compared well with that of existing climatology. The passive microwave radiometer derived sea ice extent data from National Snow and Ice Data Centre (NSIDC), Colorado, USA were used to compute the sea ice melting in different sectors of the Antarctic during the month of December. It was found that the sea ice melting in the Indian Ocean region has a significance correlation with the barrier layer formation in the study region.
80 Ocean Society of India OSICON Proceedings 13-15 July 2011
ABSTRACTS
THEME-9 ATMOSPHERE & OCEANS-CLIMATE CHANGE
Ocean Society of India 81 AOCC-1 Response of Aerosol Optical Depth (AOD) to the General Cycle of Global Climate in the Western and Eastern Indian Ocean Shalin Saleem, KV Sanilkumar, CA Babu* and CVK Prasada Rao Naval Physical and Oceanographic Laboratory, Ministry of Defence, DRDO, Kochi-21 *Department of Atmospheric Sciences, CUSAT, Foreshore Road, Kochi-16
The western and eastern Indian Ocean has been receiving attention for the last one decade in terms of the Indian Ocean Dipole (IOD). Positive, neutral and negative phases of the IOD are identified based on the Sea Surface Temperature (SST) in these regions. The response of IOD is reflected in all the atmospheric parameters viz. atmospheric winds, pressure, humidity, amount of rainfall, air temperature etc. Therefore, real-time information at closer spatial interval on any atmospheric parameters from these regions has got significant importance in the field of climate studies. In this regard, ocean colour sensors of satellites give an atmospheric parameter Aerosol Optical Depth (AOD) at closer spatial interval of 360 m x 360 m. With a view to take the advantage of this high resolution data to understand the climate change, a study is undertaken utilising AOD data of SeaWiFS (September 1997 – December 2010). Good response for AOD to the cycle of IOD and El Nino in the western and eastern regions of the Indian Ocean especially during 1997 and 2006 was noticed. One of the reasons for this response may be different sources of AOD during the occurrence of these atmospheric phenomena. In order to identify the sources of the aerosols in the study regions during different epochs of these climatic cycles, HYSPLIT model developed by the Aerosol Optical Laboratory, USA was used and traced back the trajectory of aerosols at three atmospheric levels of 1000, 950 and 700 mb using. The study revealed that the sources of aerosol supply in the study regions vary during the periods of IOD / El Nino.
AOCC-2 Effects of Atmospheric Interferences on Coastal HF Radar Measurements Rajnish Antala, Manu P John, and B. K. Jena National Institute of Ocean Technology (NIOT), Chennai - 600100
Coastal High Frequency (HF) Radar signal is affected by atmospheric interference (wind and cloud), sea state, ionospheric effect, and extra-terrestrial activities. Recent studies on effect of HF Radar signal shows that effects of these parameters have major control on
82 Ocean Society of India OSICON Proceedings 13-15 July 2011 the quality of data reception. In the present study the data quality of HF Radar signal along Indian coast have analyzed and found the effect of ionosphere is dominant compare to other parameters.
Coastal HF Radars are operational along east and west coast of India including Andaman and Nicobar islands for ocean surface current measurement and high wave activities. It uses seawater as its’ medium for transmission and reception of the Radar signal. The recent data analyzed at all sites along Indian coast shows that the radial coverage of data decreases from day to night. At Kalpakkam site the maximum range of 216.5km during day time recedes to 70km at night, where as it recedes 140 to 120km at Machilipatanam, 210 to 160km at Gopalpur(along east coast of India) and 180 to 80km at Jegri site(along west coast of India). However, the signal is also affected by various atmospheric and terrestrial activities. This study gives an overview of these effects along Indian coast.
AOCC-3 On the Relative Roles of Onset Vortex and Mini Warm Pool over the Arabian Sea on the Monsoon Onset over Kerala M.R.Ramesh Kumar and Syam Sankar National Institute of Oceanography, Goa - 403004
The inter-annual variability, in the formation of the mini warm pool (MWP, sea surface temperature > 300 C) over the Arabian Sea (AS), and its role in the formation of the monsoon onset vortex (MOV), has been examined using the recently released high resolution Hamburg Ocean Atmosphere Parameters and fluxes from Satellite data (HOAPS 3), NCEP/ NCAR Reanalysis circulation at 850 hPa, and the outgoing longwave radiation (OLR) dataset for the period 1988 to 2005. The present study examines the role of sea surface temperature, evaporation, wind speed and integrated columnar water vapour, the low level jet at 850 hPa and OLR in the formation of the MWP, as well as MOV over the AS. We further examine the role of various ocean atmosphere parameters over the AS during the onset vortex years, as well as during non-onset vortex years for better understanding their role in relation to MWP and MOV. The low level wind circulation at 850 hPa clearly showed that they were formed only in those years when the LLJ was conducive for its formation. The study further explores the reasons for the presence or absence of MOV over AS. Even though an MWP was present over the AS one pentad prior to MOK, during most (13 out of the possible 18 years) of the study period, the MOV has formed only during three years (1994, 1998 and 2001), indicating its insignificant role on MOK.
Ocean Society of India 83 AOCC-4 Climate Change and its Impacts on Marine Fisheries P. Nammalwar, S.Satheesh and R. Ramesh Institute for Ocean Management, Anna University, Chennai – 600025
Global warming and the resulting climate change are among the most serious environmental problems facing the world community. Climate change has the direct impact largely on the coastal marine environment and their living resources especially fisheries. These climate impacts alter the availability of living marine resources, affects species biodiversity, productivity of the ocean and timing of seasonal biological events. Rising global temperature is expected to raise sea levels, change precipitation and other local climate conditions. The seas around as dictate terms in deciding the climate and weather. They cover around 70% of the global surface and play a vital role in sustaining biodiversity and fishery resources. India’s food and water security systems will be the worst victims of a rise in mean temperature. Building our defence against potential climate change activated calamities through mainstreaming climate resilience in all developmental programmes should be the priority task today. The ocean plays a vital role in India’s economy by virtue of their resources, productive habitats and wide biodiversity. The presently emerging anthropogenic climate change has an impact on the performance of the global player ‘ocean’ as well as on the risks in coastal zones and their resources.
Climate changes predicted as a result of increases in green house gases are likely to impact coastal aquaculture systems. Rising sea level inundate coastal aquaculture farm lands enhance saltwater intrusion make coastline retreat and force shift to salt tolerant activities like shrimp farming. Towards the end of 21st century, the projected sea level rise will affect low lying coastal areas. This will damage many coastal ecosystems such as mangroves and salt marshes which are essential for maintaining many wild fish stock as well as supplying seed to aquaculture. Climate change impacts on aquaculture have both direct (e.g. through physical and physiological processes) and indirect (e.g. through variation fish meal supplies and trade issues). The physical changes related to climate change, i.e. in temperature, solar radiation, current and wave actions, sea level rise, water stress, and the frequency of extreme events, will impact physiological, ecological and operational (e.g. species and site selection, containment technologies etc.) processes. Positive impact of climate change on aquaculture includes food conversion efficiencies and growth rates of finfishes and shellfishes in warm waters. The present paper provides a review of potential impacts of climate change on marine fisheries.
84 Ocean Society of India OSICON Proceedings 13-15 July 2011
AOCC-5 Impact of Rossby Wave on Variation of Indian Summer Monsoon Dhrubajyoti Samanta, M K Dash and P C Pandey Indian Institute of Technology Kharagpur, Kharagpur, India – 721 302
Indian Summer Monsoon (ISM) is one of the important phenomena in the tropical calendar. Proper understanding of ISM (June to September) has profound importance to south Asian hydrological cycle. Indian subcontinent experiences anomalous southerlies in the deficit monsoon year and northerlies during the excess monsoon year due to spatial phases of Rossby wave during these periods.
The present paper describe the behaviour of the Rossby wave during normal, excess and drought years over the Indian Ocean in the wind and Outgoing Longwave Radiation (OLR) pattern. The monthly wind and the OLR anomalies have calculated by subtracting the climatology from that of the monthly values. The climatologies have generated considering only the normal ISM years. The wind pattern shows cyclonic vortex around north-east part of Indian Ocean during drought years like 2002 and 2009. OLR pattern shows the occurrence of deep convective cloud in normal monsoon years between 70E to 100E, whereas same is located between 90E to 120E during drought years. Shifting of Rossby wave pattern is observed along zonal direction in the OLR anomalies during 2002 and 2009. Pressure-Longitude cross section of potential vorticity shows anomalous breaking of Rossby waves in drought years between 50E and 70E. It affects the monsoonal convection process and the rainfall.
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ABSTRACTS
THEME-10 (A) MARINE ECOSYSTEMS ME-1 Impact of Coastal Processes and Geomorphology on turtle nesting along Orissa coast, East coast of India P.K. Mohanty1, S.K.Patra1, B. Seth1, U.K Pradhan1, B. Behera1, S. Barik1, P.K. Kar1, S. Bramha2, P. Mishra3 and U.S.Panda3 Department of Marine Sciences, Berhampur University, Berhampur-760 007, Orissa 1NIOT,Chennai, 2IGCAR,Kalpakam, 3ICMAM Project Directorate, NIOT Campus, Chennai-600100
Orissa has three mass nesting beaches, the rookery near Rushikulya river mouth, Devi river mouth and Ekakulanasi near Dhamara. Olive Ridley Sea Turtles are nesting en masse at these rookeries that fluctuate from year to year. The objective of the present study is to assess the impact of coastal processes and the geomorphology of beaches on the nesting behavior and its interannual variability.
The information on beach profile, areas and volume of sediment transport, shoreline change, surf zone width, hydrographic conditions (salinity and TSS) and sediment grain size of nesting beaches were collected near Rushikulya every month from June 2008 to December, 2010. Information on waves, currents and winds were collated for the specific periods of mass nesting to understand what triggers it. Beach profiles indicated that narrow beach width due to erosion and higher beach slope led to decline in mass nesting. Continuous northward growth of the spit resulted in erosion immediately to the north and hence gradual shifting of the nesting beaches further north. The grain size analysis indicated that the nesting beaches have mean grain size of coarse to medium (0.5-1.4 phi) and are polymodal in distribution. Sediments are very well sorted in the foreshore and midshore (<0.35 phi), moderate to poorly sorted in the backshore (0.5-2.0 phi). The results suggest that depositional environment from November to March; low tidal range(0.85m), low wave activity (0.5-1m), stable and flat beach, high saline water(32-33), low suspended solid concentration and high productivity provide a conducive environment for mass nesting of Olive Ridley Sea Turtle. Analysis of wind direction and speed from 1994 to 2009 for the periods of mass nesting indicates that almost 180o shift in the wind direction, increase in wind speed and the associated wave conditions, and onset of southerly wind act as precursor for triggering the mass nesting on the particular day. Triggering of mass nesting on 10th February, 2009 also satisfied the above wind conditions besides a shift in the current direction from northerly to southerly and a drop in the current speed from 0.4 m/s to 0.15 m/s.
88 Ocean Society of India OSICON Proceedings 13-15 July 2011
ME-2 Bacterial Abundance in Godavari Estuary: Influence of River Discharge on Bacterial Metabolism D.T. Manjary, V. R. Prasad, L. Gawade and V.V.S.S. Sarma National Institute of Oceanography (CSIR), Visakhapatnam
Heterotrophic bacteria are important key components in any aquatic system and are the major mineralisers of organic carbon and nutrients where the organic carbon can be recycled back into the food webs or accumulated into bacterial biomass. The source of organic carbon to the estuary can be either from in situ primary production (Autochthonous) or from external terrestrial inputs (Allochthonous). Estuaries act as intermediates in exporting the organic matter from land to the coastal waters and modifies significantly before it is discharged to the coastal ocean. Thus, it is important to study the variations in bacterial abundance in the estuary with reference to changes in organic carbon concentrations to understand recycling of organic matter. Bacterial abundance was measured along with physical and biogeochemical properties in the surface waters of the Godavari estuary at three fixed locations from April 2009 to March 2010. The high bacteria counts were associated with peak river discharge (>2000 m3 s-1) and were decreased during moderate (<2000 m3 s-1) and no discharge periods. The high bacterial abundance was associated with low total organic carbon (TOC) suggesting high bacterial respiration rates. The incubation experiments suggested high bacterial carbon demand and bacterial respiration rates during peak discharge period compared to low discharge period indicating that significant amount of allochthonous carbon was utilized during peak discharge period. In addition to this, the TOC concentrations decreased by ~10-30% in the estuary before they were discharged to the coastal region suggesting that significant amount of organic carbon was decomposed in the estuary by microbial oxidation. Such high decomposition rates were further supported by warmer waters (>28o C), high nutrients, and low salinity as bacterial metabolism is more active in such conditions than marine waters with low nutrients. In addition to this, high bacterial numbers were also found during May and October when phytoplankton blooms were occurred suggesting that in situ production of organic carbon might have supported bacterial carbon demand. Incubation experiments suggested that heterotrophic respiration is several folds higher than the autotrophic production and oxidation of allochthonous carbon making estuary as a net sink for organic carbon and strong source for CO2 to the atmosphere.
Ocean Society of India 89 ME-3 Studies on Effects of photosynthetically active radiation in Chlorophyll a during Post monsoon season off Cochin waters Minu P, S.S Shaju, G. Archana, P. Muhamed Ashraf, B. Meenakumari* Central Institute of Fisheries Technology, ICAR, Matsyapuri P.O., Cochin 682 029, India *Indian Council of Agricultural Research (ICAR), New Delhi 110 012
Under water light availability of different waters are impacted by seasonal changes in the dominant constituents of each class of substance. Availability of underwater light is a critical factor for primary production by phytoplankton in the water column. The relation between photosynthetically available radiation and Chlorophyll a concentration has been carried out during September 2010 to April 2011.The light parameters such as remote sensing reflectance; photosynthetically active radiation (PAR) etc of the water column has been examined at 2hours interval using Hyperspectral radiometer. The results highlighted that chlorophyll a concentration is directly influenced by photosynthetically active radiation. The variability of chlorophyll a with seasons is due to the attenuation of light by change in suspended particles and CDOM. The results suggest that factors affecting light attenuation should be considered during the modelling of algorithms for remote sensing applications.
Key words: PAR, Chlorophyll absorption, CDOM, Radiometer
ME-4 Vertical and Horizontal Distribution of Chlorophyll ‘A’ and Phytoplankton from Pondicherry-nagapattinam Waters, Southeast Coast of India P. Sampathkumar, K. Kamalakannan, C. Thenmozhi, R. Sankar and T. Balasubramanian Annamalai University, Parangipettai- 608 502
The present study was carried out to know the vertical and horizontal distribution of Chlorophyll ‘a’ and Phytoplankton from 3 different stations viz. Pondicherry, Parangipettai and Nagapattinam for a period of one Year from April 2009 to March 2010. The samplings were carried out at a distance of 0.5Km, 1Km, 1.5Km, 2.0Km, 2.5Km and 3Km from the shore and vertically at various depths viz. 5m, 10m and 15m. Dissolved oxygen content ranged from 4.089mgl-1 to 5.329 mg l-1, Chlorophyll ‘a’ ranged from 0.019µgl-1 (at surface waters) to 54.765 µgl-1 (15m depth) and the Primary productivity values ranged from
90 Ocean Society of India OSICON Proceedings 13-15 July 2011
6.0mgCm-3hr-1 to 189.31 mgCm-3hr-1 from all the three stations. In general the Chlorophyll ‘a’, Primary Productivity and Dissolved Oxygen concentration were higher during summer season than the other seasons. The present study recorded a total of 87 species of planktonic diatoms, 25 species of dinoflagellates and 2 species of blue-green algae from all the 3 stations. Simple correlation (r) was made for the statistical interpretation of the dissolved oxygen, Primary productivity, Chlorophyll ‘a’ and phytoplankton distribution.
ME-5 Seasonality in the Distribution and Abundance of Macrobenthic Fauna in the Cochin Estuary and Adjacent Coastal Shelf T.V. Rehitha, N. V. Madhu, R. Reshmi, G. Vijay John and C. Revichandran National Institute of Oceanography, Regional Centre, Kochi-682018
Seasonal changes in the distribution and abundance of macrobenthic fauna of the Cochin estuary and adjoining coastal waters were studied during the premonsoon and monsoon 2010. During the premonsoon, the estuary was dominated by high salinity waters (24.5±7.4) due to the incursion of seawater, while during monsoon, the system was flooded with freshwater (2.6 ± 3.1) due to heavy river discharge associated with the torrential rainfall. Generally, the sediment texture was silty clay and clayey sand in the estuary during the premonsoon and monsoon periods, whereas it was silty clay and sandy clay respectively in the coastal waters. A distinct spatio-temporal variation in macrobenthic abundance was evidenced in the study area, in which higher abundance was occurred both in the estuary (av. 2055 ind. m-2) as well as in the coastal waters (av. 2080 ind. m-2) during the premonsoon as compared to the monsoon period (av. 1480 ind. m-2 & av. 886 ind. m-2). Polychaetes formed the most abundant group (50-90%) in the estuary, mostly belong to the family Capitellidae and Spionidae, which followed by Oligochaetes, Bivalves, Gastropods, Amphipods, Isopods, Decapods etc. On the other hand, Foraminifera was the predominant group in the coastal waters, followed by Polychaetes, Bivalves, Gastropods and Amphipods.
Key words:- Macrobenthos, Cochin estuary, Polychaetes, Foraminifera, Monsoon
Ocean Society of India 91 ME-6 Plankton metabolic activity and its role on dissolved organic carbon dynamics in a tropical lagoon, Chilika: India K.Vishnu Vardhana*, R.S.Robina, Pradipta R Mudulia, B.Charan Kumarb, A.Lova Rajub, D.Gangulya, S.Patraa, G.Nageswara Raoc, A.V.Ramanb and B.R.Subramaniana aICMAM Project Directorate, Ministry of Earth Sciences, NIOT Campus, Chennai 600 100, India bDepartment of Zoology, MB Laboratory Andhra University, Visakhapatnam 530013, India cDepartment of Inorganic and Analytical Chemistry, Andhra University, Visakhapatnam 530013, India
In recent years, the carbon cycle has receives more attention by the researchers due to the increase of carbon dioxide in the atmosphere and the adverse climate change caused by the green house effect. Organic matter is one of the biggest carbon reservoirs in the world and plays an important role in biogeochemical cycles of carbon in the marine and coastal environments. Dynamics of dissolved organic carbon (DOC) and particulate organic carbon (POC) was studied at 35 stations in the Chilika Lagoon during May (Premonsoon) and October (Monsoon) 2009. Mean DOC & POC concentrations were found to be 309.7± 171.8µM & 239.3± 224µM during premonsoon and 200 ± 77.4µM & 128.5 ± 73.37µM during monsoon, respectively. Both showed a distinct spatial and temporal distribution along the salinity gradient. Earlier studies revealed that DOC was influenced by various physical, chemical, and biological processes. Production of new organic carbon (primary production) is one of the factors that could lead to alter the DOC concentrations in the lagoon through the metabolic activity of phytoplankton. Therefore, we studied the primary production (POC) and rate of extra cellular released DOC using liquid scintillation counting technique at 11 stations representing the entire lagoon. The extracellular release of DOC was found to be highest in central sector followed by northern, southern and outer channel. Results showed that the production of DOC and POC varied from 15.8 – 77.8 mg C m3d-1 & 82 – 296 mg C m3d-1 during premonsoon and 12.9 - 69.2 mg C m3d-1 & 62.5 – 182.3 mg C m3d-1 during monsoon, respectively. Significant positive correlation was observed irrespective of seasons between POC and extracellular released organic carbon. The percentage of extracellular released organic carbon was varied from 12.6- 21.3% (Premonsoon) and 17.2-28.6% (Monsoon) that of the new production of POC. This indicated that as a net ~20% of the fixed inorganic carbon in the lagoon was instantaneously accessible for the mineralization process. Monsoonal impact lead to a reduction in the primary production by 42.8% with that of premonsoon where as the extracellular release decreased only 26.6% signifying the importance of external stress on DOC dynamics.
Keywords: Plankton metabolism, extracellular release, dissolved organic carbon dynamics, Chilika Lagoon, New production
92 Ocean Society of India OSICON Proceedings 13-15 July 2011
ME-7 Influence of allochthonous input on trophic switch over and
CO2efflux in a shallow tropical lagoon Chilika lagoon, India R.S. Robina*, Pradipta R. Mudulia, K.VishnuVardhana, B. CharanKumarb,Shoji D. Thottathild, U.S.Pandaa, Sivaji Patraa, T. Balasubramanianc, A.V. Ramanb and B.R. Subramaniana aICMAM Project Directorate, Ministry of Earth Sciences, NIOT Campus,Pallikaranai, Chennai 600 100, India bDepartment of Zoology, Marine Biological Laboratory, Andhra University, Visakhapatnam 530 013, India cCentre of Advanced Study in Marine Biology, Faculty of Marine Science,Annamalai University, Parangipettai, 608 502. Tamil Nadu, India. dCentre for Ecological Research, Kyoto University, Japan
In the last decade, a lot of effort has been put to understand the role of heterotrophicbacterioplankton in the proceses of organic carbon in aquatic systems. Knowledge of primary productivity (PP), bacterial productivity (BP), bacterial abundance (BA) and bacterial respiration (BR) are prerequisiteto understand the transformation and mineralization of organic matter as the balance between these variables determines the trophic status of the system. As known the BP/PP and PP/BR ratios are >1 and <1, the system becomes heterotrophic and vice versa, soBP, BA and BR were examined in relation to PP for the first time in the Chilika Lagoon during 2009for the estimationof its trophic status. The seasonal variation of BP ranged from23.33 – 99.3, 28.49 – 176.23 and 23.33 – 99.3 µg C L-1 d-1 during pre-monsoon, monsoon and post-monsoon respectively. BR varied from 16.33 – 331.3 µg C L-1 d-1 inpre-monsoon, 19.15 – 397.37µg C L-1 d-1 in monsoon and 11.25 – 320.7 µg C L-1 d-1 during post-monsoon. BA exhibited spatial and temporal variability ranging from 0.32x 109 to 1.45 x 109 cells L-1 and was significantly correlated with lagoon salinity (p< 0.01). BA during the southwest monsoon (1.45 ± 0.57 x 109 cells L- 1) and post-monsoon (1.11 ± 0.47 x 109 cells L-1) were higher than pre-monsoon (0.97 ± 0.43 x 109 cells L-1). During pre-monsoon,PP was in the order of 66 – 884 µg C L-1 d-1 and it ranged 24 – 872 µg C L-1 d-1, 76 – 764 µg C L-1 d-1during monsoon and post-monsoon respectively. A wide spatial and temporal variation in the tropic status were observed in the lagoon apparent by BP/PP(0.02 – 4.25) and PP/BR (0.15 – 44.12) ratios. Thenet pelagic seasonal shift in production from autotrophy to heterotrophy due to terrestrial organic matter inputsviarivers enhanced the bacterial heterotropyas well aspCO2 (10134µatm) -2 -1 during the monsoon. Corresponding net CO2 efflux was -26.51 to 311.35 mmol m d and -26.66 to 427.41 mmol m-2 d-1 during pre-monsoon and post-monsoon respectively. However, its magnitude was two fold higher during the monsoon (-24.18 % 713.52 mmol m-2 d-1). The north sector of the lagoon wasidentified as heterotrophic andcharacterized by low PP, high BP and high BR, which leads to oxygen undersaturation and exceptionally
Ocean Society of India 93 high pCO2. This study reveals that the elevated CO2supersaturation in the northern sector caused by increased bacterial respiration (in excess of PP) was a result of bacterial degradation of allochthonous organic matter.Alsoit indicates,the lagoon being part of coastal ecosystem, receives huge riverine organic flux during summer monsoon with 60% annual rain fall (June-September). A major fraction of this organic load gets trapped and biologically respired making the system a net source of CO2 to the atmosphere instead of exporting to the sea. As a pioneering attempt, our studies on seasonal and temporal variations in bacterioplankton biomass, production and respiration along with dissolved gases (O2 and CO2) revealed that lagoon acts as ‘‘net autotrophic’’ during pre-monsoon and post-monsoon, whereas ‘‘net heterotrophic’’duringmonsoon. Onspatial scale south, central and outer channel recorded ‘‘net autotrophic’’, while the northern sector shows‘‘net heterotrophic’’ during all the season.
Keywords: Primary Productivity; Bacterial Productivity; Respiration; CO2Supersaturation; Heterotrophy; Tropical Estuary.
ME-8 Estimating Chlorophyll-a Concentration using first - Derivative Spectra in Coastal Waters of Bay of Bengal along East Coast of India K.Gopala Reddy, Srikanth Ayyala Somayajula, B. Srinivasa Rao Center for Studies on Bay of Bengal, Andhra University, Visakhapatnam
The technique of derivative analysis is applied to estimate algal chlorophyll concentration in Western Bay of Bengal coastal waters along East Coast of India. The data was collected over different sampling stations during January to May-2010. A Satlantic™ hyperspectral ocean colour radiometer (HyperOCR) was used for measuring downwelling irradiance
(Ed (ë, z)), downwelling irradiance reaching the sea surface (Es (ë)), and upwelling radiance
(Lu (ë, z)), measurements. The instrument operates in 255 channels of optical data with wavelengths ranging from 300 to 1200 nm (350 to 800 nm standard) with a bandwidth of ± 10 nm in visible bands and ± 20 nm in near infrared (NIR) bands. The results indicated that first derivatives at 490-500 nm, 555 – 565 nm and 670-680 nm were correlated strongly with chlorophyll-a. The R values reached 0.91 for the wavelengths from 555-565nm. The results shows that the derivative spectra are an effective tool for estimating chlorophyll concentration and support the hypothesis that derivative spectra are less impacted by wave effects.
94 Ocean Society of India OSICON Proceedings 13-15 July 2011
ME-9 Application of a Ecosystem Model to Study the Dynamics of Nutrients in Chilika Lagoon
Uma Sankar Panda, Sivaji Patra, R.S. Robin, K.VishnuVardhan, Pradipta R. Muduli, D. Ganguly and B. R. Subramanian ICMAM-PD, NIOT Campus, Chennai-600100
To illustrate and calculate the important physical, chemical and biological processes of the lagoonal ecosystem of Chilika (N 190 28’-190 54’; E 850 06’-850 35’), a coupled hydrodynamic, advection-dispersion and ecosystem model has been developed using Mike 21 modelling tools. The current study provides a concept to develop a new ecosystem model for a complex and dynamic coastal environment where significant spatial and temporal variation prevailed. The conceptual model is successfully calibrated and is able to simulate the spatial and temporal variation of Chlorophyll, nutrients and other water quality constitutes in response to the variation of boundary and weather conditions. Validations are being made with the in-situ observed data. The skill test shows a good agreement of the simulated parameters. These result shows that, in the northern and central sector, the variation of water quality constituents such as COD, Chl-a, PO4–P and DIN follows a seasonal pattern, high during the rainy seasons and low during winter. This is because runoff from land areas during the rainy seasons contributes nutrients load and runoff water dilutes seawater in areas near the inlet. Totoal loadings of nutrients have been estimated for each sectors of the lagoon. The model is found to be able to compute the mass budgets and residence time.
ME-10 Distribution of Benthic Polychaete Species and relation with Biogeochemical factors in East Coast of India S.A. Naidu, and V.V.S.S. Sarma National Institute of Oceanography (CSIR), Regional Centre, Visakhapatnam
Benthic Polychaetes are the dominant taxa in marine environment and play key role in food chain at various trophic levels. Several studies have been conducted in the east and west coast of India to understand their distribution however influence of water column and sediment properties on their distribution is rather sparse. In this study 18 sediment samples were collected off mouth of estuaries in the east coast of India during peak discharge period (July-August 2010) at a depth of 25, 50, and 100 m. Surface water
Ocean Society of India 95 phytoplankton biomass, represented as chlorophyll-a, increased towards northwestern coastal Bay of Bengal, where low suspended sediment matter was observed. This led to penetration of light into the water column and increase in phytoplankton biomass. Dissolved oxygen concentrations were also decreased to <10 mM at 100 m water column depth in the northwestern coastal Bay due to high production in the surface resulting enhanced sinking carbon and their microbial degradation at depth. The sediment organic carbon increased towards northwest and their isotopic ratios suggests >60% of organic carbon has marine origin in the north. All these conditions in the northwestern coastal Bay of Bengal are conducive for benthic plankton growth. A total of sixty five polychaete taxa were identified in the study region. The density of polychaete taxa were increased towards northwestern coastal Bay of Bengal from south and it was consistent with water column and sediment characteristics. High diversity was observed close to the coast (at 25 and 50 m) and decreased towards offshore. The dominant species in south and north were Prionospio pinnata, Nephtys cornuta, and Ancystrosyills parva, Lumbrenereis sp respectively. Lavinsenia Spp., A .parva Spp. Cossura coasta were numerically significant at the offshore stations (100 m) off river Krishna, Mahanadi and Godavari whereas Prionospio spp. is dominant close to the coast (<50 m water column depth) off Krishna and Godavari than offshore. Occurrence of deposit feeders and organic indicator species were decreased towards offshore and it is consistent with the organic carbon content in the sediments. This study therefore suggests that spatial distribution of polychaetes were mainly controlled by the water column and sediment characteristics along the east coast of India.
Keywords: Benthos, Polychaete, in fauna, Bay of Bengal, organic carbon, and Chlorophyll.
ME-11 Meso-scale Atmospheric Events Promote Phytoplankton Blooms in the Coastal Bay of Bengal K. MANEESHA, and V.V.S.S. SARMA National Institute of Oceanography, Visakhapatnam
The Bay of Bengal is considered to be a low productive region compared to the Arabian Sea based on conventional seasonal observations. Such seasonal observations are not representative of a calendar year since the conventional approach might miss episodic high productive events associated with extreme atmospheric processes. We examined here influence of extreme episodic atmospheric events, such as heavy rainfall and cyclone, on phytoplankton biomass in the western Bay of Bengal using both in situ time-series observations and satellite derived chlorophyll-a (Chl-a) and Sea Surface Temperature (SST). Four times increase in Chl-a concentration in the coastal Bay was observed in two
96 Ocean Society of India OSICON Proceedings 13-15 July 2011 weeks following the supply of nutrients through runoff driven by episodic heavy rainfall (234 mm) on 4-5th October 2007. Similar increase in Chl-a, by 3 to 10 times, was observed on the right side of the cyclone Sidr track in the central Bay of Bengal. These two episodic events caused phytoplankton blooms in the western Bay of Bengal which enhanced ~40% of fishery production during October-December 2007 compared to that in the same period in 2006. Therefore it is important to include influence of episodic events on annual production when it is compared with the adjacent basin, Arabian Sea.
ME-12 Environmental Factors Controlled by Phytoplankton biomass and Production rate in the Estuarine Waters of Cochin Dayala V.T and Sujatha C.H Department of Chemical Oceanography, CUSAT, Cochin.
The spatial and seasonal variations in hydrographic conditions offered by the estuarine waters of Cochin, helps to understand the relationship between physico chemical variables and phytoplankton abundance, which form the main objective of the present study. Cochin estuary one of the largest estuary in India (256km2), this micro tidal estuary undergo a characteristic transformation from a river dominated system during summer monsoon, to a tide dominated system during pre monsoon season. The estuary is enriched by the enormous input of nutrients (nitrite, nitrate, phosphate and ammonia) from various sources was responsible for the high phytoplankton biomass irrespective of seasons. The changes in the phytoplankton biomass, production rate and species composition were studied during the year (2009-2010), of three seasons with respect to environmental parameters. The phytoplankton community was in general dominated by diatoms in pre monsoon season. The optimum nutrients and light intensity prevailing the mesotrophic condition have enhanced the abundance of diatoms in the estuary. During post monsoon season, the light limitation due to high turbidity reduces the diatom growth and abundance even though high nutrients level exists. In monsoon the flora was only constituted by green algae and the abundance was very low. The production of phytoplankton in the Cochin estuary varies seasonally and is found to be sensitive to the environment.
Keywords: Cochin estuary, phytoplankton, environmental parameters
Ocean Society of India 97 ME-13 Diurnal variation of Plankton in Godavari Estuary M.D. Bharathi, V. Venkataramana and V.V.S.S. Sarma National Institute of Oceanography (CSIR), Regional Centre, Visakhapatnam
Diurnal variations in plankton (phyto and mesozooplankton) composition were measured at fixed location in the Godavari estuary during wet and dry periods. Phytoplankton composition during dry period (February) was dominated by Bacillariophyceae followed by cyanophyceae and dinophyceae. On the other hand, cyanophyceae was dominant during wet period (June) followed by Bacillariophyceae and dinophyceae. The diurnal variations in the phytoplankton abundance and composition followed tidal cycle viz high abundance associated with high tide and vice versa during dry period and contrasting to that was observed during wet period. The major diatoms species, namely Coscinodiscus, Merismopedia, Nostoc, Nitzchia, Thalassiosira spp. were high during low tide than high tide in wet period and same species showed opposite behavior during dry period. Over all, mesozooplankton biomass was higher during high tide than low tide during both wet and dry periods. Such behavior was mainly driven by high mesozooplankton abundance at the mouth than upstream. In addition to this, mesozooplankton abundance was an order of magnitude higher during wet period than dry period. This suggests that the different behavior of phytoplankton to tides during wet and dry period were driven by grazing pressure rather than tidal influence alone. The grazing rate during June was 1.5 d-1 which was lower by 3 times during February (0.5 d-1). Such high grazing pressure during June influenced diversity and dominance of phytoplankton as well. For instance, dominance and diversity was 0.810±0.11 and 0.232±0.11 during dry period whereas it was 0.398±0.056 and 0.56±3.39 respectively during wet period. Due to stable condition, saline water and less grazing pressure resulting in high dominance during dry than wet period. On the other hand, high stratification and less residence time of water (low flushing rates) in wet period resulting in high diversity. Bacillariophyceae contributed ~98% and 2% by cyanophyceae during dry period whereas bacillariophyceae contributed 26% and 73% by cynophyceae during wet period.
98 Ocean Society of India OSICON Proceedings 13-15 July 2011
ME-14 Influence of River Discharge on Phytoplankton Community Structure in the Coastal Bay of Bengal D. Bandhopadhyay, T. Acharyya, and V.V.S.S. Sarma National Institute of Oceanography (CSIR), Regional Centre, Visakhapatnam
The Bay of Bengal receives an enormous amount of fresh water from the major rivers, such as the Ganges, Brahmaputra, Godavari, Mahanadi, Cauvery, Irrawady, and Krishna (1.6 × 1012 m3 a”1), and high precipitation (~2 m a”1). The river system delivers the major parts of its annual average sediment load (1.1 × 109 t) during June to September and the fluvial inputs are major sources of nutrients to the Bay of Bengal. In order to examine the biogeochemical characteristics of different rivers and their influences on phytoplankton dynamics in the coastal Bay of Bengal, samples were collected from off river mouths along the east coast of India during the peak discharge period (July-August, 2010). It was observed that suspended particulate matter (SPM) was relatively higher in the southwestern coastal Bay with an average load of ~50 mg/l and it was decreased to <20 mg/l in the northwestern coastal Bay and similar distribution pattern was observed for nutrients as well. As a result of increase in light penetration in the north led to enhanced phytoplankton biomass and decrease in nutrients in the northwest than southwestern coastal Bay. Phytoplankton pigments also showed contrasting differences between southwest and northwestern coastal Bay. Fucoxanthin (diatoms) concentration was less (<1ug/L) in the southwest and increased significantly (2 to 3 ug L-1) in the northwest and contrasting to this was observed for perdinin (dinoflagellates). Such spatial differences were mainly caused by different nutrient ratios in the coastal Bay of Bengal. The mean N:P ratios in the southwest was ~8.1 whereas it was ~5.0 in the northwestern Bay. Low ammonium and nitrate concentrations were observed in the northwestern Bay where high dinoflagellates were observed due to their preferential consumption of reduced nutrients. Though high ammonium concentrations were observed in the southwestern Bay however dinoflagellates were almost absent due to non-availability of light driven by high suspended load. On the other hand, zeaxanthin concentration did not show contrasting differences between north and south except that higher concentrations were observed off Godavari and Mahanadi where high ammonium concentrations were observed. In conclusion, physical and biogeochemical properties such as salinity, nutrients ratios and suspended matter, play a great role on phytoplankton community structure in the coastal Bay of Bengal.
Ocean Society of India 99 ME-15 Development of Water Quality Index for Coastal Region of Visakhapatnam Using Statistical Techniques Sangeeta Pati, M. K. Dash, C. K. Mukherjee and B. Dash Indian Institute of Technology Kharagpur *Central Marine Fisheries Research Institute, Visakhapatnam
Continuous monitoring of physical, chemical and biological parameters of coastal water in a continuous manner is very essential for Marine Aquaculture. So it is desired to turn complex water quality data into a single number that expresses overall water quality of a certain location at a particular time. This paper proposes a technique to describe the water quality quantitatively for the marine aquaculture from multiple measured water quality parameters through an index called Water Quality Index (WQI). Different water quality parameters, like Dissolve Oxygen (DO), Biological Oxygen Demand (BOD), Total
Suspended Solid (TSS), Ammonia (NH3), Phosphate (PO4), Nitrate (NO3) at different depth has been collected for each month for 0.8° (along latitude) ×0.2° (along longitude) box near Visakhapatnam coastal zone of Bay of Bengal from 2007 to 2010.
Theses data have been classified into number of groups using multivariate analysis. Hierarchical Agglomerative Cluster Analysis (HACA) is carried out in the Euclidean space to classify the groups. Three groups of water quality i.e. good, average and poor have been identified. The groups are undergone F test and found statistically significant under 1% level of significance. The relation between any two groups has been studied using discriminant function analysis. A suitable discriminant function has been generated to describe the maximum variance in the data set. Group centroids are calculated using the discriminant function for each group. The WQI has been generated using these values and found within the range -1 to +1. The negative value representing the centroid for potentially good and positive value representing poor water quality based on the eigen values assigned to each water quality parameters. The interval -1 to +1 establishes a range of average condition of coastal water. The WQI derived using this method has been tested taking some random samples and found to be robust. This work has shown that WQI generated using this multivariate procedures proved to be an efficient tool to understand the status of the coastal water.
100 Ocean Society of India OSICON Proceedings 13-15 July 2011
ME-16 “River discharge”: A Critical Factor Controlling Phytoplankton Biomass and Community Composition in Monsoon driven Godavari Estuary T. Acharyya, D.Bandyopadhyay and V.V.S.S. Sarma National Institute of Oceanography, Visakhapatnam – 530017
Indian subcontinent houses some of the worlds’ largest estuaries (Ganges, Godavari, Krishna, Narmada etc.) which plays prominent role in particulate organic carbon (POC) fluxes in the adjacent coastal ocean. A major portion of that POC is contributed by estuarine phytoplankton and it is customary to understand their fate all through their journey from estuary to sea. Additionally, phytoplankton, which lie at or near the bottom of the food chain, support secondary and tertiary production in the estuary in terms of economically important fish, prawn and mollusc. However, the phytoplankton community composition, species succession pattern and their dynamics, both in terms of spatial and temporal scales, are fairly unknown in this region.
To address this knowledge gap, three year (2007-2009) extensive daily time series observation was carried out in the Godavari river estuary which opens into the Bay of Bengal, east coast of India. Our observation suggests that Godavari estuary is characterised by high flushing rate and turbid water column during the peak monsoon season (July- September). Even though a lot of nutrient is brought into the estuary by this time, phytoplankton population are not able to increase their biomass due to severe light limitation. During the withdrawal phase of monsoon (by October), consequent reduction in the discharge volume coupled with stronger incursion of the tidal wedge stratifies and stabilises the water column. A month long phytoplankton bloom (contributed by Cyanobacteria) coincides with this stratification event, which we call as the ‘major bloom’. Crashing of this bloom takes place when salinity in the estuary gradually peaks up by November which put Cyanobacteria under osmotic stress. Our in-vitro experiment suggests the salinity tolerance maxima of the inhabiting Cyanobacteria population in Godavari river estuary is about 16 PSU( Practical Salinity Unit).Niche left by Cyanobacteria is steadily occupied by diatoms which are far more salt tolerant and thrive in the clearer water column. Diatom population contribute a ‘minor bloom’ by April and sustain their standing stock until the next cycle of discharge starts by July. Major bloom intensity as well as the bloom sustenance was enhanced from 2007-2009 which is inversely correlated with volume of discharge that facilitated enhanced stability and higher residence time of the water parcel in the estuary. Sensitivity of the Indian estuaries towards the
Ocean Society of India 101 eutrophication and thus overall health of these ecosystems is tuned by variability in monsoon rainfall. It requires further study keeping in mind with the climate change scenario that would bring inevitable change in the rainfall pattern.
ME-17 Coastal and off shore Phytoplankton Pigment Profile of North Bay of Bengal with reference to TSM and Turbidity Sanghamitra Palleyi, R. N. Kar and C. R. Panda Institute of Minerals and Materials Technology, Bhubaneswar
The coastal Bay of Bengal is a unique marine environment in the tropical belt with marked continental influence due to the drainage by a large number of rivers. The Bay of Bengal is considered to be low-productive zone which is strongly affected by monsoons, storm surges, and cyclones but has no seasonal upwelling. The Bay of Bengal marine ecosystem is considered a Class II, moderately productive ecosystem based on SeaWiFS global primary productivity estimates. In such a significant area, knowledge of phytoplankton dynamics and distributions is vital to ensure a scientific basis for coherent management of the coastal environment and the human activities which impact on or benefit from it. Extensive study was conducted to investigate the phytoplankton pigment spectrum, and associated water chemistry of Bay of Bengal region from Odisha to West Bengal. Water samples were collected for pigment analysis from near shore to off shore regions of Bay of Bengal, conducting different cruises during the year 2009-2011.
The objective of this study is to generate in situ data on pigment profile which will be helpful for monitoring programs to assess environmental controls on ecosystem structure and function over varying spatial and temporal scales on the areas of Bay of Bengal region from Odisha to West Bengal. Large scale study over oceanic and near-shore region revealed that high concentrations of pigment were observed near the estuarine region. Result of Chlorophyll-a distribution patterns during 2009-10 ranged from 0.23-8.80 µg/l in the near shore regions and 0.02-4.48 µg/l in the off shore regions. The upper range of pigment concentration was observed at the near shore region of Dhamra estuary during December’10. Chlorophyll concentrations of 3.74-8.80 µg/l at Dhamra have been observed as a consequence of high proliferation rate of phytoplanktons during winter. The off shore active chl-a and pheopigment concentration was highest in Dhamra transect i.e. 4.2186 µg/l and 2.7661 µg/l respectively. Carotenoid pigment (photo protective pigment) was also highest in Dhamra (1.3381 µg/l) in comparison to Mahanadi and Haladia transect. Higher concentration of pheopigment in the off shore regions of Mahanadi and Dhamra transect at 10 and 20 meter depth indicates high rate of grazing. The vertical distribution
102 Ocean Society of India OSICON Proceedings 13-15 July 2011 of pigment reveals that at Dhamra off shore transect the pigment distribution in the shore line area was very much stratified in comparison to Mahanadi and Haladia. At Mahanadi transect the subsurface and bottom layer chlorophyll maxima were observed after 20 meter depth. A positive relationship was observed for TSM, turbidity and primary productivity with chlorophyll. During October’10 at the near shore region of Dhamra estuary, the relationship of TSM and turbidity with chlorophyll is found to be inverse. Among TSM and turbidity, turbidity has got a strong relationship with chlorophyll.
ME-18 Spatial Distribution of Zooplankton along Orissa Coast in Dry Season Suchismita Srichandan, N. C. Rout and C. R. Panda Institute of minerals and Materials Technology, Bhubaneswar
Oceans are Earth’s most distinctive feature covering about 71% of its surface. The entire spectrum of life found in the pelagic realm of oceans and their associated coastal embayment are categorised under three basic types, namely plankton, nekton and pleuston. The plankton community is divided into three groups; (1) phytoplankton (plants), (2) zooplankton (animals), and (3) bacterioplankton (bacteria). Zooplankton represents an important component of marine life forming important compartment(s) of food web between the primary producer phytoplankton and carnivorous fish. In fact, success or failure of the fisheries of the coastal waters often depend upon the zooplankton production. The goal of this study is to determine the spatial distribution of zooplankton relative to the ecological characteristics from nine coastal areas of importance of Orissa coast such as Gopalpur (port and industrial area), Rushikulya (ecologically sensitive area), Chilika (Ramsar Site), Puri (a moderately urbanized area), Konark (pollution due to township sewage), Paradip (port and industrial area), Mahanadi (effluents from fertiliser and phosphate industries brings attention), Dhamra (highly influenced by agricultural run-off) and Chandipur (municipal sewage affected). The study was conducted during summer season (March/ April) of 2010. The ranges of air and surface water temperatures (°c) were 26.40 – 35.70 and 27.10 – 30.20 respectively. pH, salinity (PSU), DO (mg/l), and BOD (mg/l) values varied from 8.13– 8.45, 24.32 – 28.96, 6.55 – 7.90 and 0.36 – 3.26. The inorganic nutrients (mmol/l) viz. nitrate, nitrite, ammonia, phosphate and silicate varied from 1.15 –20.11, 0.12 – 1.15, 0.27 – 4.02, 0.13 – 2.81 and 3.96 – 17.06. Zooplankton density and biomass ranged from 481 – 5685 nos.m-3and 0.04 – 9.60 ml m-3 respectively. Simple correlation analyses were made between the zooplankton density with ambient water temp, salinity, dissolved oxygen, biological oxygen demand, nitrite, nitrate, ammonia,
Ocean Society of India 103 phosphate, silicate, chl-a contents, phytoplankton standing stock and zooplankton biomass to assess the influence of these hydrographic features and phytoplankton standing stock on zooplankton distribution in Orissa coast. The density of zooplankton was maximum at Mahanadi and minimum at Gopalpur. Totally forty groups of zooplankton were recorded. Out of the 40 zooplankton forms, 22 groups belonging to holoplankton and 18 different types of meroplankton were encountered. Among the holoplankton copepod formed the dominant group at all the sampling sites. The presence and array of juvenile forms in the dry season suggest that the coastal water remain a sanctuary, nursery and breeding grounds for aquatic species. Crustaceans dominated the spectrum of the juvenile forms.
ME-19 Oscillating Environmental Responses of the Eastern Arabian Sea Vijay John Gerson, Madhu. N. V, Jyothibabu. R, Balachandran. K. K, Maheswari Nair, Revichandran C. National Institute of Oceanography, Regional Centre, Kochi-682018
Characteristics of two distinct physical processes, the coastal upwelling and convective overturning, which enhance phytoplankton productivity in the west coast of India, are discussed in this paper using the comprehensive in-situ data collected during two monsoon (summer and winter) periods. During northwest monsoon (NWM), the process of winter convective mixing lead to occurrence of cold sea surface temperature (25-26°C), deeper MLD (>70m) and higher nutrient levels (1-2µM) in the upper water column (above 100m) of the northeastern Arabian Sea. In addition, pronounced oxygen deficient condition was also observed in the intermediate depths (150-300m) of the northeastern Arabian Sea during this period. On the other hand during the southwest monsoon (SWM), the process of coastal upwelling causes the incidence of colder (27°C), low oxygenated (<190µM), nutrient rich (nitrate- >2µM) water in the southeastern AS. In both regions, phytoplankton biomass (chlorophyll a) was relatively higher (av. > 2mg m-3) during both NWM and SWM periods due to the elevated levels of nitrate (1-2µM). Even though both processes enhance phytoplankton growth in the west coast of India, the time and area of occurrence found to be entirely different. Physically forced chemical changes in the upper layers appear to play a key role in phytoplankton response, which enhances the primary productivity and impart an oscillating environmental condition to the eastern Arabian Sea.
Key words: Upwelling, winter cooling, nutrients, chlorophyll a, primary production
104 Ocean Society of India OSICON Proceedings 13-15 July 2011
ABSTRACTS
THEME-10 (B) BIO-GEO CHEMISTRY OF OCEANS
Ocean Society of India 105 BCO-1 Variability of DMS and its Related Compounds along the East Coast of India R. Viswanadham, V.D. Rao and V.V.S.S. Sarma National Institute of Oceanography (CSIR), Regional Centre, Visakhapatnam
A systematic time series study of Dimethyl sulphide and supporting biogeochemical parameters has been carried out along the east coast of India. Two different locations were selected for the proposed study, i) The Goutami Godavari Estuary(GGE) ii) coastal waters off Vishakhapatnam (VSP). The DMS and its precursor Dimethyl sulphoniopropionate (DMSPt) concentrations ranged from 0.10nM to 60.84nM and 0.14nM to 48.95nM respectively at GGE. The concentrations are increasing towards coast with maximum concentrations occurring at the mouth of the estuary. DMS and DMSPt at upstream are correlated with biomass (Chlorophyll) but such significant correlation is not observed in the coastal waters off GGE. This difference was caused due to high contribution of DMS releasing phytoplankton (Chlorophyceae) in the upstream to the total phytoplankton biomass whereas high diversity was noticed in the downstream of GGE. Observed DMS and DMSPt off VSP are in correlation with biomass with highest concentrations found at sub surface depths of near coastal stations with decreased concentrations away from the coast. The DMS and DMSPt off VSP were contributed by diatoms in the surface while dinoflagellates in the subsurface. The range of concentrations for DMS and DMSPt off VSP are lower (0.5 to 19.5 nM and 0.3 to 33.5nM respectively) than off GGE due to low biomass of DMS contributing phytoplankton.
BCO-2 Temporal Variability of Dissolved Inorganic Carbon Budget from a Tropical Shallow Lagoon, Chilika, India Prdipta.R.Mudulia, K.Vishnu Vardhana, R.S. Robina, B. Charan Kumarb, A.Chandra Moulib, U.S.Pandaa, Sivaji Patraa, G. Nageswarara Raoc, A.V.Ramanb, B.R. Subramaniana aICMAM Project Directorate, Ministry of Earth Sciences, NIOT Campus, Chennai 600 100, India bDepartment of Zoology, Andhra University, Visakhapatnam 530 013, India cDepartment of Inorganic and Analytical Chemistry, Andhra University, Visakhapatnam 530 013, India
A land ocean interaction in coastal zone (LOICZ) biochemical model was applied on a semi enclosed Chilika lagoon in seasonal basis (Active flow and Lean flow) to obtain
106 Ocean Society of India OSICON Proceedings 13-15 July 2011 water, salt and dissolved inorganic carbon (DIC) budget. The result suggests that there was a net water flux and salt residual flux towards coastal waters from lagoon, during both active and lean flow period. This study revealed that exchange between lagoon water with the ocean replaces this exported salt via mixing.The estimated freshwater discharges in to the lagoon was 3.69 x 106 m3 d-1 during the lean flow and as high as 28.34 x 106 m3 d- 1 in active flow. Water residence time during active and lean flow was calculated to be 45 and 147 days, respectively. The non-conservative DIC budget (“DIC sys) showed the lagoon served as a net sink of DIC and its magnitude increases three fold higher during active period than that of the lean period.Seasonal variation of riverine DIC flux shows a strong influence on its residual and mixing fluxes. DIC flux was found six times lower during lean flow (Vr DICr =6.08 x 109 m3 d-1) than that of active flow (Vr DICr =38.45 x 109 m3 d-1). Higher mixing flux (-7625.75 m3 d-1) during active flow relative to the lean flow (-1698.06 m3 d-1) indicated that the lagoon acts as net sink of DIC. The residence time of DIC in the lagoon water was almost twice the water residence time during both active(76 days) and lean (349 days) flow.Since the resident time of DIC is longer than the water residence time, it could be possible to allow the active biological uptake, which is evident from estimated negative “DIC sys during both periods. Application of LOICZ biochemical model on the lagoon DIC leads to the accurate estimation of advective transport of DIC which could give new insight to carbon biogeochemistry.
Keywords: DIC flux, LOICZ, non-conservative flux, budgets, Chilika lagoon
BCO-3 Source and Fate of Terrestrial Organic Carbon in Sediments along the East Coast of India
MSR Krishna, VVSS Sarma, Lata G, SA Naidu, Ch V Subbaiah and P Praveen Kumar National Institute of Oceanography – Regional Centre, Visakhapatnam, India
Rivers transport huge amount of terrestrial organic matter to the coastal ocean via estuaries. Most of this terrestrial organic matter (~80%) is believed to be recalcitrant and not bio- available. In order to understand the contribution of terrestrial organic carbon and its modifications by biogeochemical processes, we determined stable isotopic composition 13 15 of organic carbon (ä Corg) and total nitrogen (ä N) in the sediments and particulate organic 13 matter collected along the east coast of India. Isotope ratios of organic carbon (ä Corg) ranged from -28.4‰ to -19.2‰ and nitrogen isotopic ratio (ä15N) varied between -8.4‰ to 7.2‰ in particulate organic matter. Carbon to nitrogen ratio (C:N) varied broadly
Ocean Society of India 107 from 2 to 30 with lower ratios in the northern part of the coast. Strongly depleted both carbon and nitrogen isotopes and lower C:N ratios in particulate organic matter suggest 13 that major contribution of terrestrial/artificial material to this region. Using ä Corg in the simple two end member mixing model, we computed the contribution of terrestrial organic carbon to this region and it varied between 5 and 50% with higher terrestrial contribution 13 in the southern part of the coast. In sediments, ä Corg ranged from -23.3‰ to -17.6‰ and ä15N varied between 3.7‰ to 13.5‰ in surface sediments. When compared to particulate organic matter in the surface waters, sediments are enriched by ~6‰ in the case of carbon and ~5‰ in the case of nitrogen indicates that either advection of this terrestrial material to the deep ocean or the degradation within the water column. From the depletion of dissolved oxygen concentrations in the sub-surface layers of the water column, it seems that most of the terrestrial organic carbon is getting modified/decomposed within the water column by active biogeochemical processes resulting in the enrichment of carbon and nitrogent isotopic composition.
BCO-4 Seasonal Trends in the Aerosol Components over the Cochin Estuarine System Jose Mathew, Gayathree Devi and Sujatha C.H* *Department of Chemical Oceanography, CUSAT, Cochin-16, Kerala, India
The physico chemical parameters of ambient atmospheric gases and particulates were pooled over the topographically important, diverse reaction centre on the Cochin Estuarine System during the pre and post monsoon of 2010-2011.The Sampling sites selected were adjacent to the estuarine system which further classified into three zones based on salinity. Water samples were also collected to ascertain an alliance with the atmosphere. Atmospheric gases mainly focused are Sulfur dioxide, Nitrogen dioxide, Ammonia and trace metal component of the particulate matter. The meteorological parameters like wind speed; direction, temperature, relative humidity and atmospheric pressure were found to have a firm impact on the dispersive mechanism of the pollutants. Decreasing trends in the collected gases were observed from the pre to post monsoon. The La Nina and as a result continuous precipitation may have a choice to this reason. The trace metals studied include Al, Cu, Fe,Cd,and Zn. Iron varied from 0.38 to 0.84ppm. Lead was found to be in a constant ratio which indicates continuous control measures have been adapted.
108 Ocean Society of India OSICON Proceedings 13-15 July 2011
BCO-5 Seasonal Variation of Physico - Chemical Parameters in relation to Organo Chlorine Pesticides in the Cochin Estuary Salas P.M and Sujatha C.H Department of Chemical Oceanography, Cochin University of Science and Technology, Cochin
Seasonal variations of physicochemical parameters and nutrients were studied in six different stations of Cochin Estuary, the South West coast of India. Six sampling sites were selected (9o 47. 646" N and 76o 25 . 708" E to 10o 04.993" N and 76o 17. 906" E) viz Karippadam, Kumblam, Thevara, Bolghaty, Cheranellur and Kalamassery-FACT representing riverine , estuarine and three sampling surveys were conducted seasonally surface and bottom water and also sediment collected (monsoon-MNS, postmonsoon- POM, premonsoon-PRM) .During the study period DO values ranges from 1.762-7.23 mg/l in the surface water, higher at reverine region in the PRM and lower in the MNS. Same trend also seen in the bottom water. In the surface water Fe concentration ranges from 0.052-3.133 µ mol/l. Higher in PRM and lower in MNS at estuarine region. But bottom water Fe concentration higher (5.18 µ mol/l ) at estuarine region in the PRM and lower (0.063 µ mol/l ) at riverine region . Surface nitrite concentration ranges from (0.018- 3.862 µ mol/l). Higher at estuarine region in PRM and lower at riverine region in POM. Same trend also seen in the bottom water. Surface Phosphate concentration ranges from 0.783-20.2 µ mol/l, higher at estuarine and lower at riverine in the PRM season. But in bottom water higher in the POM and lower in PRM at riverine region. Surface silicate concentration ranges from 13.94-147.2 µ mol/l, higher at estuarine in the POM and lower at riverine region in the PRM period. But in bottom, water it was higher at riverine region in POM and lower in the PRM period. The correlation pattern with certain pollutants mainly organo –chlorine (OC) pesticides in these designed sites were also estimated .Above mentioned hydrographical parameters are well correlated with the OC pesticide residues in the Estuarine system.
Key words: Cochin Estuary, hydrography, organic pesticides
Ocean Society of India 109 BCO-6 Spatial and Vertical transmission Pattern of Pigments and their Assimilation with Nutrients in the Southern Ocean (SO) Water Mass Sujatha C.H, Akhil P.S, Deepulal P.M, Sini Pavithran*, Sharon B. Noronha* and N. Anil Kumar* Department of Chemical Oceanography, CUSAT, Cochin-16, Kerala, India. * National Centre for Antarctic and Ocean Research, Headland sada, Vasco-da-gama, Goa 403804 India.
Thé IVth Indian Scientific Expedition to Southern Ocean cruise was carried out from January to March 2010, onboard O.R.V Sagar Nidhi. Both surface as well as sea bottom water samples at different depths of the water column were collected from 12 stations within the Indian sector of the Southern Ocean [Latitude 390S to 650S and longitude 57030’E, 51014’E, 53032’E & 54056’E] . Study involves spatial and vertical distribution of pigments and its association with nutrients in the water column. The physicochemical parameters pH, temperature, Dissolved Oxygen and Salinity have also been noted concurrently. Southern ocean water mass shows slightly alkaline character and most of the pH values were >8. Besides there is no gradual trend in pH values during the study period and insignificant correlation pattern exist within the frontal regions. While oxygen concentration are high in coastal regions of Antarctica. An exceptionally high concentration of nitrate and phosphate was observed within the frontal regions and highest at 560S . Tremendous increase in silicate concentration was noticed towards further southern latitude. Conspicuously no enhancement of chl-a biomass was observed in the vicinity of polar front regions . In the coastal regions of Antarctica concentration of chlorophyll and other pigments was higher in surface waters . These results are useful for evaluating the round stock pigment and nutrient variation of Southern Ocean region and it will give a fundamental knowledge of these ecosystems.
Key words: Southern Ocean. Pigments. Nutrients. pH. Temperature .Dissolved Oxygen
110 Ocean Society of India OSICON Proceedings 13-15 July 2011
BCO-7 The Distribution of REE’s along South Coast of INDIA Deepulal. P.M, Gireesh Kumar. T.R and Sujatha C.H Department of Chemical Oceanography, CUSAT, Cochin-16, Kerala, India
The concentration of Rare earth elements and Yttrium (REY) were measured in sediments from nine sampling location of continental shelf region of south coast of INDIA in order to study their behaviour and distribution pattern. The REE’s are divided into LREE’s (La, Ce, Pr, Nd, Sm and Eu) and HREE’s ( Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu). REE’s were analysed using ICP-MS. Generally these samples showed high rare earth element content in sediments, with Y enrichments in the shale- normalized pattern (NASC). The sediments contain higher concentrations of LREEs than HREEs. The expected behaviour (since the REE contents of most shale and solid phases) are normally enriched in LREEs relative to HREEs. The shale normalized REEs and Y/Ho ratios additionally indicate a direct REY co-precipitation with Fe-oxyhydroxides along continental shelf and their consequent adsorption, as coating onto FeOOH surfaces. The observed variation in the Y/Ho ratios suggest that different Y-Ho fractionation processes take place in the studied area. To understand the behaviour of the shelf sediments both Ce and Eu anomalies were also carried out. Concurrently the statistical analysis was done using SPSS.
Keywords: continental shelf; sediments; REEs; NASC; Ce anomaly; Eu anomaly
BCO-8 Distribution of Labile Organic Carbon in the Godavari Estuary and Adjacent Ground Waters B.S.S. Kumar, V.R.Prasad and V.V.S.S. Sarma National Institute of Oceanography (CSIR), Regional Centre, Visakhapatnam
Carbohydrates, Amino Acids and Proteins, generally called as labile carbon, are mainly produced by autotrophic organisms and play an important role in biogeochemical cycling of organic carbon in marine environments. In order to understand their distribution in estuary and interactions with ground water, concentrations of total carbohydrate (TCHO), Dissolved Free Amino Acids (DFAA), Proteins were measured at 11 stations in Godavari estuary and 22 stations in ground water along the bank of estuary at monthly interval. The estuary experienced nearly fresh water condition during the monsoon season and brackish during dry period. Concentrations of TCHO, DFAA and Proteins were significantly higher in the estuarine waters than in the ground waters. The contribution
Ocean Society of India 111 of TCHO, DFAA and proteins to total organic carbon amounted to ~10 to 60% in the estuary with significantly higher levels during peak discharge period whereas it was <20% in the ground waters with higher concentrations during peak discharge period. Low concentrations of these labile compounds in the ground water were attributed to microbial consumption and absence of autotrophic production. High bacterial abundance and respiration rates in the estuary were associated with high TCHO, DFAA and proteins due to labile in nature and easily degradable by microbial organisms. Based on the d18O of H2O in the estuary and ground water suggests that significant exchange of ground water and river occurs throughout the years and the rate of exchange increases towards mouth of the estuary. Due to increase in the water levels in the river during peak discharge period, river water penetrates to the ground water and vice versa during dry period. It has been noticed that labile carbon components contribution to the total organic carbon increased from ~10% during dry period to ~20% during wet period suggesting that significant amount of labile organic carbon exchanged to ground water to support microbiological activities. In addition to this, ~30% of labile carbon is also transported to the coastal Bay of Bengal during peak discharge period to fuel heterotrophic activity.
BCO-9 Variability of Trace Gases in the Godavari Estuary: Influence of Ground Water Exchange G. Durga Rao, V.D. Rao and V.V.S.S. Sarma National Institute of Oceanography, 176 Lawsons Bay Colony, Visakhapatnam, India
The coastal ocean is one of the most biogeochemically active zones at the surface of the Earth. Coastal ecosystems receive considerable amounts of materials from land, through weathering of rock, exchange with ground water and injection of contaminants, and exchange these materials with the open ocean. Despite the intense biological activity, the estuaries are typical sources of trace gases such as nitrous oxide (N2O) and methane (CH4) to the atmosphere. In order to understand the distribution of these gases and their controlling mechanisms in the Godavari estuary, systematic time series studies are being carried out in which data are being collected by occupying 14 stations from upstream to coastal ocean during spring and neap tide periods. CH4 and N2O concentrations ranged from 4.1 to 350 nM and from 3.4 to 25 nM, respectively, in the Godavari estuary with increasing concentrations towards the mouth of the estuary. Both CH4 and N2O concentrations were low during wet period and increased by an order of magnitude during dry period. High ammonium and low nitrate concentrations were observed during dry period suggesting nitrification is possible mechanism for N2O formation. In order to
112 Ocean Society of India OSICON Proceedings 13-15 July 2011 examine the influence of ground water exchange of trace gases on estuarine concentrations, ground water sampling was also carried out along the bank of the river at 22 locations.
High CH4 (up to1300 nM) and N2O (up to 180 nM) were found in groundwater and were an order of magnitude higher than estuarine levels. The oxygen level in the ground water was close to suboxic to anoxic conditions suggesting that denitrification may be possible mechanism for formation of N2O and CH4 by organic matter decomposition. Over all, both CH4 and N2O in the estuary increased towards mouth of the estuary and it is consistent with the higher exchange rates between ground and estuarine waters, based 18 on d O of H2O suggesting that estuary is acting as a chimney to eject trace gases, which were formed in the ground water, into the atmosphere.
BCO-10 Organic Carbon Modification in the Dam Reservoir to support Heterotrophic Carbon Demand in the Godavari Estuary V. R. Prasad, B.S.K. Kumar and V.V.S.S. Sarma National Institute of Oceanography (CSIR), Regional Centre, Visakhapatnam
The Godavari is the 2nd largest river in India and contributes significantly organic carbon to the Bay of Bengal. However, the organic carbon brought by the river is modified in the dam reservoir, where water is stored for about 6 to 8 months to conserve freshwater by the Irrigation department to be able to feed the irrigation canals and other cultural needs. Perennial heterotrophy has been observed during entire year in the estuary where 40- 90% of the heterotrophic carbon demand is attributed to be supported by the externally supplied organic carbon through river discharge. Terrestrial carbon is refractile and may not be utilized by the bacteria. In order to examine how organic carbon is modified in the dam reservoir during storage period, time-series experiments were conducted. Nutrients concentrations increased by ~5 times while Chl-a increased from ~2 to 8 mg/m3 during storage period in the reservoir. This suggests that intense decomposition of organic matter resulting in enhanced nutrient concentrations that led to high phytoplankton production. Similarly total organic carbon was also increased from ~300 to 500 ?M during storage period. The labile organic carbon (carbohydrates, amino acids and proteins) concentrations were also increased by ~4 fold during storage period due to high phytoplankton production. As a result, the contribution of labile carbon to the total organic carbon amounted to ~40-50% in the dam reservoir. During peak discharge period, phytoplankton production is low due to high suspended load however heterotrophic carbon demand is mainly met by high content of labile carbon in the discharge waters which was modified in the reservoir.
Ocean Society of India 113 BCO-11 Stable Isotopes of Carbon and Nitrogen in Suspended Matter and Sediments from the Godavari Estuary Ch.V. Subbaiah, S. A. Naidu and VVSS Sarma National Institute of Oceanography (CSIR), Regional Centre, 176 Lawsons Bay Colony, Visakhapatnam
Carbon and nitrogen content and their isotopic concentrations in the suspended matter and sediments were measured at 12 stations in the Godavari estuary to examine contribution of terrigeneous matter in the estuary. The results show significant variability in isotopic signatures was found over the entire length of the Godavari estuary. The mean 13 13 15 15 isotopic (d Csed: -26.05±2.3; d Csus: -25.36±1.7; d Nsed: 8.00±2.7 and d Nsus: 6.52±0.9 ‰) -1 and elemental (Csed:0.45%±0.2%; Csus: 154.7±30 mmol l ; Nsed: 0.07%±0.05% and Nsus:27.5±4 mmol l-1) supports a predominantly terrigenous source. Significant enrichment in isotopic ratios of d13C from upper to lower estuary in both suspended matter (-24.09 and -23.01 ‰ respectively) and sedimentary (-27.00 and -27.2 ‰ respectively) indicates decrease in influence of terrigeneous material towards mouth of the estuary. The significant positive relationship between d13C of suspended and sediment indicates that these two organic pools are rather coupled and a significant fraction of exchange is possible. Based on simple mixing model to our data indicate that about 46% of the suspended matter is contributed by the terrestrial origin and may support higher heterotrophic activity in the Godavari estuary.
Keywords: Stable isotopes, carbon cycling, biogeochemistry, terrigeneous organic matter, Estuary.
BCO-12 Sources of particulate Organic Carbon and Nitrogen in the Gautami Godavary Estuary Lata Gawade and V.V.S.S.Sarma National Institute of Oceanography (CSIR), Regional Centre, Visakhapatnam
Godavari is the largest monsoonal river in India and contributes significant amount of organic carbon to the coastal Bay of Bengal to support heterotrophic activity. It has been noticed that perennial existence of heterotrophy in the estuary with an average autotrophic production to heterotrophic respiration ratio of 0.14. It was attributed that ~40-90% of the heterotrophic carbon demand is supported by the external source of carbon and it is relatively large during wet period when autotrophic production is limited by availability
114 Ocean Society of India OSICON Proceedings 13-15 July 2011 of light due to high suspended load. Freshwater discharge brings huge amount of nutrients to the system however the source of nutrients is unknown. In order to understand source of external carbon and nitrogen during discharge and wet period, content and isotopic composition of organic carbon and nitrogen was measured in the particulate matter (POM) during different periods. During dry period the mean ä 13C of POM in the estuary was - 23.2‰ while it was -29.4‰ during wet period. The lighter d13C isotopic ratios during wet period suggests high terregeneous organic carbon inputs to the estuary and its influence decreased from upstream to downstream due to dilution with marine organic matter. Similarly the average values of ä15N (‰) of suspended particulate nitrogen in estuary was 4.41‰ during dry period and was decreased to -0.47‰ during wet period. Heavier ä15N during dry period indicates in situ production was supported by regenerated nutrients due to heterotrophic bacterial activity as evidenced from high bacterial respiration 0.95 µM C h-1 and high bacterial carbon demand 0.97µM C h-1 .Depleted d15N during peak discharge period indicates terrigeneous sources, such as fertilizers, which was again supported by high C:N ratio of 21 and lighter d13C. Bacterial productivity was linearly increased with particulate organic matter suggesting that significant amount of organic matter decomposition in the water column. Particulate organic carbon and nitrogen followed Redfield ratio of 6.6 during dry period whereas it was 9.2 during wet period indicating in situ production and terrigeneous organic matter are potential sources respectively. Based on two end member mixing model, the contribution of terrigeneous organic matter was estimated to be 80-90% during wet period while it was ~20-30% during dry period. The magnitude of terrigeneous carbon contributed was directly proportional to amount of discharge. This study suggests that significant amount of terregeneous organic carbon and inorganic nitrogen enters to the estuary to support both auto and heterotrophic activity.
BCO-13 Seasonal Variation of Water Quality Parameters at Puri, East Coast of India - A Pollution Study S.K Baliarsingh, M.K Khadanga*, & K. C Sahu Department of Marine Sciences, Berhampur University, Orissa, India *National Institute of Ocean Technology, Palikarnai, Tamilnadu, India
In the present study the seasonal variation of DO, BOD, Salinity, Chl-a, nutrients (NO2,
NO3, PO4, SIO4, NH4) and plankton diversity of coastal water were carried out. The imperative of the study was to assess the status of water quality as the study area is under anthropogenic influence. Municipal sewage canal of Puri discharges domestic
Ocean Society of India 115 wastes and organic pollutants into its coastal water that results in eutrophic condition. In the present investigation, the premonsoon DO and BOD were recorded at 3.78 mg/l and 4.01 mg/l respectively. However, it tends towards normalcy in monsoon and post monsoon seasons. High value of Chl-a concentration (18 mg/l) was recorded in postmonsoon period. Similar to the above, nutrient concentration was found to observe the same trend. The
NH4 concentration in the water samples reveals higher order of 28.89 mmol/l in premonsoon, 31.22 mmol/l in monsoon and 23.99 mmol/l in post monsoon. Such values create a setback for tourism industry as ammonia rich water is not suitable for recreational activities. That apart, it is also detrimental to nearby aqua farms and coastal fishery. The present investigation also has brought about the unusual behavior of other water quality parameters. A total of 80 species phytoplankton were documented during the entire study period but the maximum diversity was recorded in post monsoon as compared to premonsoon and monsoon. The lower diversity was recorded during pre monsoon which may be due to low dissolved oxygen value; these are likely pointers to pollution stress. Total of 58 species of zooplankton were documented in the present piece of work. Amongst those, some pollution indicators viz. phytoplankton species: Anabaena sp., Microcystis sp., Oscillatoria sp. and zooplankton species: Polydora ciliata were encountered during the study period indicating coastal pollution. The study recommends to take immediate necessary measures for sewage water treatment before it drains into the coastal water.
Keywords: Biochemical Parameters, Puri, Nutrients, Pollution
BCO-14 Dredging Impacts on the Coastal Water Quality of Dhamra, Orissa Seoul Sangita, D. R. Satapathy, R. N. Kar and C. R. Panda Environment and Sustainability Department, Institute of minerals and Materials Technology, Bhubaneswar-751 013, Odisha, India
Dhamra estuary forms an important component of the Bhitara Kanika marine sanctuary on the northern coast of Orissa, India. The water circulation of Dhamra estuary is contributed by two rivers namely Bramhani and Baitarani. Dhamra port, the newly constructed and cost-effective port on the Eastern coast of India is located at Dhamra, Orissa. It was observed that in recent years the various activities in port and harbour, basically the dredging activities affect the coastal and estuarine water quality. Considering the ecological importance of Dhamra region, the study was undertaken to assess the changes if any, by evaluating the samples collected bi-monthly. The sampling stations were selected along the stretch of river and sea interphase i.e. from port area to a distance
116 Ocean Society of India OSICON Proceedings 13-15 July 2011 of 30 kilometers into the sea covering six stations including estuarine and marine zone during April-2009 to March-2010. The study revealed that the estuary was significantly influenced by freshwater input during monsoon period. The seasonal nutrient variations (except Nitrate) exhibit higher values during monsoon season, which are related to agricultural run-off and regional anthropogenic activities respectively. The physical parameter such as pH, salinity, conductance and chemical parameters such as Total Hardness and Total Dissolved Solid increased towards the deep marine region from the inner riverine region where as the reverse trend was observed in case of nutrients, turbidity and Total Suspended Solid. BOD value is not within the permissible limit due to abnormal microbial activity. The season wise observation of DO shows an inverse trend with salinity and temperature of surface water because temperature and salinity affect dissolution of oxygen in seawater. The TSS value was high in pre monsoon period due to re-suspension of sediment from the sea bottom as a result of current and wave action. Though the nitrate - value was higher than the other two, it was observed that the nutrient values (NO3 , NH3, 3- PO4 ) are within the permissible limit. It was observed that the estuarine zone of Dhamra was significantly influenced by the anthropogenic activities and also by the fresh water input during monsoon period as it is a transition zone between river and ocean environments. The high Total Suspended Solid during dredging is a temporary phenomenon and do not grossly modify the water quality.
BCO-15 Suspended Matter Induced Nutrient biogeochemistry in a River Plume Dominated Tropical Shallow Lagoon, Chilka, India Sivaji Patra, R.S. Robin, Prdipta.R.Muduli, K.Vishnu Vardhan,U.S.Panda and B.R. Subramanian ICMAM Project Directorate, Ministry of Earth Sciences, NIOT Campus, Pallikaranai, Chennai 600 100, India
Coastal river plumes signify one of the final stages of material transport, across the land sea interference. Most studies however have focused on the behavior of small sized river plume of coastal and shelf waters, whereas large river plumes and its role on biogeochemical cycles have been neglected. This present study address the behavior and distribution of suspended particulate matter (SPM), dissolved inorganic nutrient (DIN, DIP, DSi) and chlorophyll a (Chl.a) in Chilika lagoon induced by Mahanadi river plume. Resuspension of SPM was frequently observed within the lagoon with a significant correlation with water quality parameters nutrients. The mean SPM concentration was found to be 47.76 ± 25.57 mg L-1 and 79.17 ± 96.82 mg L-1 during Premonsoon and postmonsoon respectively whereas during monsoon it reached up to 239.73 ± 345 mg L-
Ocean Society of India 117 1 .The DIN (NO3+NO2+NH4) concentrations was found highest during Monsoon (14.54 ± 7.56 ìM) followed by Postmonsoon (7.86 ± 7.29 ìM) and Premonsoon (3.04 ± 2.03 ìM). The concentration of dissolved inorganic silicate (DSi) also found high (144.59 ± 47.15 ìM) during the MN with values >200 ìM along the northern sector of the lagoon. In contrary, a substantial reduction in silicate (<20 ìM) could be noticed during the PRM. The mean N:P ratios observed to be 9.28 ± 6.09, 30.02 ± 17.53 and 6.12 ± 4.93 during Premonsoon, Monsoon and Postmonsoon respectively. From this ratio, it is evident that during Premonsoon and Postmonsoon lagoon is nitrogen limiting, whereas, MN shows phosphate as limiting with surplus nitrogen influx. Horizontal negative gradient of SPM and nutrient from the northern sector towards the southern sector depict a strong influence of Mahanadi river plume on the biogeochemistry and nutrient distribution in the lagoon. Chl.a a records suggested that only nutrients have the stimulating effect on the water column productivity in all the seasons. On the contrary, inhibitory influence (light limitation) by the SPM over phytoplankton growth was found negligible which become weaker from the northern towards the southern sector of the lagoon. Imported SPM may play a decisive role in regulating the water columns N/P ratio by desorption of nutrients to the lagoon water at a seasonal basis.
Key words: Lagoon; suspended particulate matter; nutrients; chlorophyll; river plume
118 Ocean Society of India OSICON Proceedings 13-15 July 2011
ABSTRACTS
THEME-11 COASTAL PROCESSES & COASTAL ZONE MANAGEMENT
Ocean Society of India 119 CPCZM-1 Hydrodynamic and dispersion modeling of coastal tropical lagoon: a case study in Chilika lagoon Uma Sankar Panda, V. Ranga Rao, B. R. Subramanian, R. N. Samal* and M. M. Mohanty* ICMAM-PD, Ministry of Earth Sciences, NIOT Campus, Chennai *Chilika Development Authority, Bhubaneswar - 751014, India
Numerical models act as an excellent tool to obtain the right measures and applications to restore the environments undergoing rapid degrading situations. In this study, modeling effort has been made to the Chilika lagoon, the Asia’s largest brackish water lagoon, which is undergoing rapid ecological changes in recent years. Water level and circulation was simulated, using a hydrodynamic model (HD). Driving forces such as tide, wind, fresh water inflows and major calibration factors like the bed resistance coefficient (Manning number=32 m1/3/s), the eddy viscosity coefficient (Smagorinsky formulation) and the wind friction coefficient were considered for HD model. In the advection/dispersion (AD) model, heat exchange coefficients in the Dalton’s law and Angstrom’s law equations for temperature simulation and the dispersion coefficient for salinity simulation are the major calibration factors. Both HD and AD models have been calibrated and validated with field measurements. Several sensitivity analyses have been investigated. The result shows that the southern sector found to be more stable in terms of hydrodynamics. The water level measurements with good agreement as the RMS is between measured and predicted water levels didn’t exceed the 8% of the data range during validation and the model skill equal to 0.85 near inlet, while it decreases in the main body of the lagoon. The simulated daily water temperature variations were well correlated with the data gained during the field observations. The measured and the computed time series present a model skill equal to 0.82 near Inlet, decreases in the main body. The salinity variation near the inlet shows stratification while it is homogenous throughout the lagoon.
CPCZM-2 Flux measurements at the Cochin Harbour Inlet using Acoustic Doppler Profiler C. Revichandran, K.R. Muraleedharan, V.K. Jineesh, Vijay John Gerson*, Shivaprasad Amaravayal M. Rafeeq National Institute of Oceanography, Regional Centre, Dr.Salim Ali Road, Kochi-18 *Department of Chemistry, St. Alberts College Kochi-18
Cochin estuarine system (Vembanad lake and surrounding islands) occupies nearly 320Km2 of area with six rivers flowing in to it. Seasonal river discharge and the tides
120 Ocean Society of India OSICON Proceedings 13-15 July 2011 determine the hydrodynamics and biogeochemistry of the estuarine system. Tides in the estuary are semidiurnal with periodicity of 12.42 hrs. Annual river discharge in to the system form the six rivers are estimate to be 2000M.m3 . These high fresh water empties into the sea through Cochin harbour inlet and partly through Munambam bar mouth. Cochin port trust has recently embarked on many major constructional activities, like Vallarpadam Container Transhipment terminal, marina and building of roads and bridges across the back waters. Deeping of the approach channel to facilitate bigger ships to berth at Vallarpadam terminal has altered the flow filed in the harbour region significantly. Periodic measurement of river flux across the harbour inlet is essential to quantify the nutrient and sediment transport and to assess changes in the flow due to anthropogenic activites. Acoustic Doppler Current Profiler (ADCP) is increasingly used for velocity and discharge measurements across river / estuarine channels. This paper presents the advantage and efficacy of a moving boat ADP( Sontek, ADP ,1500 Mhz) for the measurement of discharge in a distinctly two layer flow field. For the computation of residual fluxes measurements were carried out over two semi-diurnal tidal cycles at an Interval of I hour during spring and neap tide. Residual fluxes were 15.09 M.m3 and 13.20 M.m3 during Neap and Spring respectively. The excess fluxes during the neap phase eventually increase the vertical salinity stratification considerably as evidenced in the vertical salinity sections.
CPCZM-3 Impact of mining on the stability of a placer mining beach 1K.Rajith, *N.P. Kurian and *V.R. Shamji Naval Physical & Oceanographic Laboratory, Kochi 682022 *Centre for Earth Science Studies, Thiruvananthapuram 695031
The Chavara coast of southwest coast of India is fraught with environmental issues such as coastal erosion and mining. The coast is well known for the rich heavy mineral deposits, which are being mined commercially. A detailed study was conducted to understand the role of mining on erosion process along the coast. The study involved extensive field measurements and numerical modelling. Based on the results it was found that the coast under study is an open system with considerable inputs by the longshore as well as the cross-shore transports. It was deduced that the impact of mining would not significantly affect beach when the mining was within an optimum level equivalent to the quantum of sand replenished by the natural processes. If the quantum of mining exceeds this level, it could cause local impacts on the beach as well as in the innershelf area.
The mining scenario changed in the area of study since 2001. While the Indian Rare Earths Ltd. was the major player in the area till 2001, the Kerala Minerals and Metals Ltd. (KMML),
Ocean Society of India 121 expanded its mining operations in a major way starting from 2001. The combined mining by both these firms constituted a quantity much more than the annual replenishment. To verify the possible impact of this huge quantum of mining on the beach morphology, beach profile measurements were continued till 2004 at selected stations. It was seen that while station located in Kovilthottam mining site maintained its dynamic equilibrium, station located in Vellanathuruthu mining site showed cumulative loss of material showing the imbalance. It is pertinent to note that the beach adjoining the station located in Vellanathuruthu mining site was the intake area of KMML too. The result shows that the combined mining by KMML and IREL has offset the dynamic equilibrium in beach volume changes seen till 2001 at VMS 7 and it supports the hypothesis that any intake more than the annual replenishment could have serious consequences on the beach.
CPCZM-4 Acoustic Doppler Velocimeter Measurements of Surf Zone Currents along Visakhapatnam-gangavaram Coast V. Ranga Rao, S.V.V., Arun kumar*, K.V.S.R.Prasad*, Ch Venkata Ramu*, K.V.K.R.K Patnaik* and M. Manikandan ICMAM-PD, Ministry of Earth Sciences, NIOT Campus, Chennai-600100 *Dept of Meteorology and Oceanography, Andhra University, Visakhapatnam-530 003
Surf zone currents play a crucial role in nearshore sediment transport pattern along any coast. Surf zone current measurement is a challenging task because breaking waves and strong currents exert powerful forces on instruments.. For this study we measured hourly variations of littoral currents by mooring an Acoustic Doppler Velocimeter (ADV) in the mid-surf zone for two tidal cycles each at 5 stations during June 2009 along 25km coastal stretch encompassing Visakhapatnam coast. This instrument records the cross-shore (Vx), alongshore (Vy) and vertical (Vz) components of the currents following Doppler shift principle of acoustic sound signals. This insitu data has many applications in Coastal Engineering for estimating the strength of longshore currents, in identification of rip currents, and in assessing the littoral sediment transport. Surf zone currents are mainly generated due to the energy released (radiation stress) after the waves break at the shoreline i.e. they are wave-induced. Apart from the waves, tides are observed to play very crucial role in modifying the strength of the currents particularly the cross-shore (Vx) currents. The strength of Vx currents is observed to be increasing from peak low tide (slack) hours and attaining maximum within two-three hours. Therefore, it is evident from our observations that tidal stage is modulating the nearshore currents. The strength of the Vy currents is varying accordingly with the height of the offshore waves. The alongshore currents are weak within a range of 0.1-0.2 cm/s and are undulating along the
122 Ocean Society of India OSICON Proceedings 13-15 July 2011 coast. The cross-shore currents are relatively stronger (0.3-0.5 m/s) and are directed offshore. Stronger cross-shore currents were recorded at RK Beach and Yarada; indicating that these two beaches are vulnerable for rip current formation. In a sheltered bay at Jonnalakonda, both the currents are observed to be very weak.
CPCZM-5 Intra-annual Varibility of Wave Characteristics at a Nearshore Location in West Coast of India K. Jossia Joseph and B. K. Jena National Institute of Ocean Technology, Pallikaranai, Chennai, India-600100.
The wave characteristics and its variability are of great significance in offshore and near shore engineering. Long term time series data is required to identify the characteristics of the waves at the area of interest. The wave data collected off Vijayadurg at 17m water depth during October 2006 to September 2007 at an interval of one hour is utilised in this study to delineate the intra-annual variability at this location. The significant wave height is less than 1m with an average wave period of 6s except during southwest monsoon season. The significant wave height ranges between 1.5m to 5m during June to September which indicates the rough sea state during the south west monsoon. The mean wave direction is predominantly westerly and varies between west southwesterly and west northwesterly whereas the swell waves remain steady southwesterly. The energy in the swell component is in general less than that of sea component except during southwest monsoon. The wave energy in the swell component is higher than the sea component and exhibits the same direction as that of mean wave direction during the southwest monsoon. The sea state at this location is greatly modified by the presence of strong swells during southwest monsoon.
The analysis of wave spectra exhibits the dominance of double peaks over single peaks at this location. The wave spectra exhibit mainly single peak during southwest monsoon season and double peaks for rest of the year. Multiple peaks in the spectra are also observed but with lesser percentage of occurrence and is not specified to a season. The most of the major peak in the double peaked spectra is observed in the sea component with spectral peak between 4.5s and 7s. The spectral peak in the swell component varies from 11s to 17s and mostly exhibits the secondary peak in the spectra. The spectra with equal peaks in sea and swell component are also observed but with lesser frequency. Similarly there are a few occurrences of swell dominated double peaked spectra. The wave spectra changes to single peak by the end of May and remains till the end of September with spectral peak in the swell component. A slow transition in spectral peak is observed during southwest monsoon from 14s to 9s. The wave characteristics at this location reveal the dominance of swell waves and double peaked spectra which requires special attention in the design of structures.
Ocean Society of India 123 CPCZM-6 Assessment Of Shoreline Changes Of Chennai, Tamil Nadu Using Gis (3D Vectorisation) and Digital Image Processing Techniques R. S. Kankara, B. Rajan*, S. Chenthamil Selvan*, V. Ram Mohan* Integrated Coastal and Marine area Management Project Directorate, Ministry of Earth Sciences, Government of India, Pallikaranai – 600 100, India *Department of Geology, University of Madras, Maraimalai Valagam, Chennai – 600 025, India
About 23% of the Indian coastline is affect due to coastal erosion and coastal protection works have been carried out at various locations along the coast. Shoreline changes are one of the serious problems in several pockets along Indian coast. The coastline has been subjected to several geo-morphological changes due to natural processes and manmade activities and the shoreline evolution is of major concern for coastal communities. The shoreline retreat leads to loss of beaches and consequently to set back of the coastline that threatens the coastal communities. The changes in shoreline s are generally seasonal due to changes in wind, waves, currents, and sediment transport. Further, the additional changes occur when perturbations are introduced by anthropogenic factors/activities of coastal zone. The information about shoreline changes is the basic requirements for all the coastal infrastructure projects and sustainable coastal zone management. Shoreline changes are dynamic in nature and demand constant monitoring. The Remote Sensing & GIS are very useful to understand the long-term process of shoreline changes. In this paper, attempt as been made to use these techniques to analysis the long term shoreline changes along Chennai coast. The study was conducted for 15 km long coastal stretch between Thiruvottiyur to Thiruvanmiyur covering Marina and Besant Nagar tourist beaches to study shoreline changes occurred in last 4 decade. The details of satellite data and field data used in the study were given in the following table.
S.NO YEAR OF DATA TYPE OF DATA’S RESOLUTION
1 1972 LANDSAT (MSS)–REMOTE SENSING 57M
2 1991 LANDSAT (TM)–REMOTE SENSING 28.5M
3 2000 LANDSAT (ETM)–REMOTE SENSING 28.5M
4 2007 CARTOSAT-1–REMOTE SENSING 2.5M
5 2008 RTK–GPS–FIELD SURVEY <5CM (ACCURACY)
6 2007, 2011 ARC-PAD GPS –FIELD SURVEY <3M (ACCURACY)
124 Ocean Society of India OSICON Proceedings 13-15 July 2011
The remote sensing datasets were geo-referenced in image processing software (ERDAS) by Polynomial 2nd order using Universal Transverse Mercator (UTM) projections and World Geographic System (WGS 1984) datum. Landsat images were used, to extract the shoreline automatically by image processing techniques. 5th band of Landsat image was classified into 2 classes and shoreline was automatically extracted from the classified images. Cartosat image is overlaid on Cartosat DEM for manual 3D vectorisation. The 3D view of Cartosat DEM was generated to distinguish the shoreline. The extracted shoreline was verified from field survey (GPS data). Finally, the periodical shoreline changes for 39 years were analyzed for the entire coastal stretch using DSAS (Digital Shoreline Analysis System) statistical stand-alone tool. The results confirm that the shoreline in the northern region of the port was eroded at the rate of -4.2m/y and southern part of the study area (MARINA) is extending EASTWARD (Seaside) with a rate of 1.4m/yr for past 39 years. However, after construction of groins along the Royapuram region, the erosion rate was marginally reduced and small beaches formation is noticed around few groins. The CARTOSAT data was found very useful for Shoreline Change Studies.
CPCZM-7 Management of Shoreline Morphological Changes due to Breakwater Construction along a Stable Coast V.Noujas1, K.O.Badarees1, N.R.Ajeesh2, L.Sheela Nair1, T.S.S.Hameed1 and K.V.Thomas1 1 Centre for Earth Science Studies, Trivandrum 2 National Institute of Technology Karnataka, Surathkal [email protected]
Kerala coast is considered to be one among the highly eroding coastal sectors and the impact of erosion is the highest due to the thickly populated narrow coastal belt. The major factors influencing shore stability along the Kerala coast are construction of harbour breakwaters, coastal protection structures, sand mining and occurrence or disappearance of mud banks. Various researchers have studied the scenario of shoreline changes along this coast with respect to the above factors at different locations. In the present study, the processes of shoreline morphological changes along a stable, high energy coast are analyzed using numerical models to propose management options to tackle the morphological modifications.
The coastal stretch from Veli to Varkala has two identifiable sediment cells separated by the Muthalapozhi inlet with harbour breakers on either side of the inlet. The construction of breakwaters has caused substantial erosion immediately north of the inlet and beach
Ocean Society of India 125 build up south of the inlet. The harbour mouth gets blocked due to deposition of beach sand, virtually making the harbour unusable. Shoreline changes, near shore processes and beach characteristics along this sector are studied through extensive field observations. These observations are used to calibrate and validate sediment transport and shoreline change models for this coast.
Sediment transport and shoreline changes are simulated using different modules of LITPACK model. Monsoon erosion is characterized by events of short period steep waves, which occur as repeated events of few days during monsoon season, transforming the normal profile of pre-monsoon to storm profile with a bar-trough configuration. The storm profile moves onshore-offshore depending on the breaks in the monsoon. The beach building period following monsoon has longer period swells bringing back the beach sediment, which is a long drawn process over a period of few months. Hence the behavior of coast during monsoon is simulated using LITPROF module of LITPACK. The process during beach building period has been simulated using shoreline evolution model LITLINE. The calibration of the model is done with field observations. It is found that beach sediments get deposited on south side of the breakwater and bypassed sediment gets deposited at the inlet mouth. The validated model is used to simulate the processes with different designs and a groin field of smaller groins of length comparable with the surf zone width during beach building period, about 600 m south of the breakwater, has been found best suited to control the choking of harbour mouth due to sediment deposition.
CPCZM-8 Investigation of Geomorphic Processes on Mulky - Pavanje Rivermouth, West Coast of India Gumageri Nagaraj and Dwarakish G S National Institute of Technology Karnataka Surathkal
Coastal regions, in particular the regions around the rivermouths are highly complex and dynamic environment; undergo significant spatial changes in a relatively short span of time. These regions never ever maintain a morphological equilibrium and create crucial management problems. In the current study, Mulky - Pavanje rivermouth, central west coast of India is selected to understand the geomorphic processes occurring in and around the rivermouth. Textural characteristics of the surficial sediments were studied on a monthly basis to understand the geomorphic response of the region, by selecting eight locations on either side of the rivermouth for a period one year, from September 2009 to August 2010. Sediments have been investigated for their textural characteristics; mean
126 Ocean Society of India OSICON Proceedings 13-15 July 2011 grain size, sorting and skewness. Textural analyses indicated that foreshore sediments near the rivermouth during pre-monsoon were dominated by fine grained, well sorted and positively skewed, whereas away from the rivermouth dominated by coarse grained, well to moderately well sorted and negatively skewed sediments. However during the monsoon the foreshore was dominated by coarse grained at all locations and during the post-monsoon sediments changed to medium to fine grained, well to moderately well sorted and dominantly symmetrical positively skewed sediments. This indicates a distinct seasonal variation in textural parameters at all locations and the variations are highly significant from one location to other.
CPCZM-9 Enhanced stratification during Neap Tide of Godavari Estuary B. Sridevi, V.V.S.S. Sarma and T.V. Ramana Murty National Institute of Oceanography (CSIR), Regional Centre, Visakhapatnam.
Godavari River is the second largest river in India which originates in the Western Ghats near Nasik at an altitude of about 1620 m and flows eastwards through Godavari graben to join the Bay of Bengal covering a distance of 1480 km. At confluence it forms a huge delta region. The daily variations in fresh water discharge are controlled by a century old “Low Dam” at Dowleiswaram where Godavari splits into Gowthami-Godavari and Vasista-Godavari, which is about 60 km from upstream (Kotipalli). In order to examine the desertification-stratification variability from spring to neap tide, hourly CTD data was collected along the estuary at 5 locations and currents data at middle of the Gowthami- Godavari estuary (Yanam) at an interval of 10 min for 7 days during peak discharge (September, 2008; wet period) and 10 days during no discharge periods (February, 2009; dry period).
The mean river discharge during wet period was 27560 m3 s-1. The salinity distribution in the estuary suggests that saline water intrudes into the estuary up to about 40 km from the mouth during dry season, which was about 25 km during wet period. The flow along the axis of the estuary is the dominant feature of the circulation and there is a weak cross- shore flow. The zonal velocities are nearly 10 times higher during September than February which suggests the existence of two layer structure. The brunt-vaisala-frequency, shear and richardson’s are ranging from 20 to 25 (radian/sec)2, 2.6 to 4.4 (1/sec)2 and 5.59 to 9.17 during wet and 1.5 x10-3 to 4 x10-4 (radian/sec)2, 0.24 – 2.28 (1/sec)2 and 6.2x10-4 – 19.6x10- 4 during dry period respectively. Computed shear and brunt-vaisala-frequencies were increased during neap than spring tide with decrease in richardson’s number suggesting that stratification was increased during neap than spring tide. The values of richardson
Ocean Society of India 127 and Froude numbers suggest that estuary is in well-mixed and salt-wedge during dry and wet periods respectively. The presence of sand dune affected the flow direction from spring to neap tide and strengthening the cross-shore flow.
Key words: Gautami-Godavari, spring-neap tides, brunt-vaisala-frequency, richardson’s number, Froude number
CPCZM-10 Role of bottom friction in a tidal estuary under combined action of waves and currents and its validation Chitra Arora and Prasad K. Bhaskaran Indian Institute of Technology Kharagpur
Waves propagating into near-shore coastal environments are subjected to energy transformation where bottom friction plays a dominant role in the redistribution process of energy density spectrum. The extent of wave energy dissipation is governed by conditions of the sea-bottom. The state-of-art wave models assume resistance law from bottom interaction due to sandy beds. The effects due to bottom friction in a heterogeneous bottom environment can vary due to changing water levels. In a tidal dominated estuary, change of water level associated with reversing currents are expected which can lead to time dependent change of water depth at any given location. Hence, the changing water level has direct implications on associated bottom friction arising due to waves and currents. The state-of-art wave models like SWAN (Simulating Waves Near-shore) use three different formulations for bottom friction viz; JONSWAP, Collins and Madsen. Though these three formulations are semi-empirical in nature and based on laboratory and field studies, its implementation in SWAN is based on time independent constant value for any given study area. This can lead to under/over-estimation of wave energy for a given water depth by choosing any of the three appropriate bottom friction formulation. The practical implications being gross approximation in studies relevant to the estimation of sediment transport and sediment budget analysis. In view of this there is an apparent need to develop a time varying bottom friction formulation that takes into account the combined action of waves and currents and associated shear in a tidal dominated estuary. The present work reports on development of a new resistance formulation for bottom friction and its implementation in SWAN model which takes into account the combination of waves and currents prevalent in an estuarine environment. The study region chosen was the Hooghly estuary located in head Bay region in the Bay of Bengal. The spatial distribution and characteristics of bottom sediments in this estuary were obtained based on reports of IRS-1A measurements. The setup of SWAN runs
128 Ocean Society of India OSICON Proceedings 13-15 July 2011 comprises GEN3 physics of Komen with Triad wave-wave interaction and turning on the white capping dissipation. Four different case studies were made each with different bottom frictional formulations. The comparison of significant wave heights with the existing and developed bottom friction formulations were then investigated with ENVISAT satellite based measurement in the Hooghly estuary. The results suggests that the new formulation to be in close agreement with measurements and hence its application for wind-wave modelling studies in coastal waters.
CPCZM-11 Prospects for Developing a Minor Port Facility at Betul, Goa Thomas Mathai, Satish Kumar, K.N. Rajarama, P. Praveen Kumar and M. Suresh Chandran Marine and Coastal Surveys Division, Geological Survey of India
Escalating industrial development and localization of special economic zones in the Konkan sector warrants the enhancement of infrastructural facilities especially in regard to shipping and cargo movement. Heavy shipping traffic has totally congested both the ports of Goa and Karwar. The development potential for setting up a minor satellite port at Betul, a coastal village with its small fishing harbour, is immense. Located at the mouth of the Sal River, the Betul area is strategically located between Goa and Karwar which, if developed into a minor port, could help divert some of the medium to small vessels and help ease the congestion. A ruined concrete jetty projecting for about a mile from the shore, east north east of Moliem point, testifies to a probable pre-existent port that had silted up. Sal River is presently navigable from the sea only by country boats and fishing trawlers during high tide; the thick and extensive sand bar almost sealing the river mouth is a big impediment to even small-scale shipping and fishing activities in this sector. A short and narrow wharf on the southern side of the river mouth was being used by small craft to transport iron ore to barges at anchor but now the activity is dormant, being duly hampered by the siltation at the river mouth. Strategies presently being adopted for dredging out deeper parts of the Sal river outflow sector have apparently not brought about any appreciable deepening to facilitate any shipping traffic and at the most can only afford short-term benefits. The Marine and Coastal Surveys Division of Geological Survey of India, initiated preliminary, integrated geological, geotechnical and geophysical surveys off Betul for making an appraisal of the developmental possibilities of setting up a minor port in this sector. Detailed surveys were carried out for preparation of a bathymetric map of the area. Shallow seismic and Magnetic surveys formed part of the geophysical underway surveys besides scanning the seafloor in the proposed channel alignment sector. The studies also included collection of sediment cores to evaluate the
Ocean Society of India 129 sub-seabed sediment package and visualize the seabed sediment distribution. Geotechnical analysis of the sediments helped to prepare a geotechnical map of the area. Basic data on pollution was also generated from seawater samples besides recording environmental parameters in order to establish background values for post-development comparison. Very well developed proximal beaches at Canaguinim Bay and Rama Bay have proven to be excellent tourist attractions. The surveys reveal that both bays could provide excellent anchorages for Cruise liners and pleasure craft; the Rama Bay, in particular, is well protected on the south by a huge natural promontory in the form of a gabbroic ridge jutting out into the sea. Dual utility of this sector in the backdrop of enhanced impetus to eco-tourism and the imminent need to cater to the pleasure sailing crafts that frequent this area with its high tourist potential could thus be well addressed. The overall assessment therefore ascribes an immense potential for the establishment and development of a minor port and related facilities in the Betul sector.
130 Ocean Society of India OSICON Proceedings 13-15 July 2011
LIST OF OSI LIFE MEMBERS
LM-001 LM-007 Dr N.BAHULAYAN Sri. A DHURKADAS VANCHIYIL HOUSE N.P.O.L, THRIKKAKARA P.O, VALATHUNGAL (PO) KOCHI-682021 ERAVIPURAM PH:0484 2422947 QUILON -18 EMAIL:[email protected] KERALA LM-008 Dr. J SWAIN LM-002 TARANG NIVASIX/639- G LINK REGIONAL CENTRE, VALLEY,LIVRA-11, KUSUMAGIRI NATIONAL INSTITUE OF OCEANOGRAPHY, PO.KAKKANAD, KOCHI-682030 SALIM ALI ROAD, PH:0484 2424911 KOCHI 18, KERALA EMAIL:[email protected] MOB:9447233286 EMAIL:[email protected] LM-009 Dr. MP AJAIKUMAR LM-003 N.P.O.L,THRIKKAKARA P.O, Sri. V. CHANDER KOCHI-682021 7C, NJK SIVAM PH:0484 2424911 LAYAM ROAD KOCHI-682011 LM-010 PH:0484 -2362615 Dr. PV HAREESH KUMAR EMAIL:[email protected] N.P.O.L,THRIKKAKARA P.O, LM-004 KOCHI-682021PH:0484 2423009 EMAIL:[email protected] Dr. C.V.K PRASADA RAO N.P.O.L, THRIKKAKARA P.O, LM-011 KOCHI-682021 Sri. ANAND P. MOB:9446594250 N.P.O.L,THRIKKAKARA P.O, EMAIL:[email protected] KOCHI-682021 MOB: 9846314883 LM-005 EMAIL:[email protected] Dr. RAO VSN TATVARTI CASTLE LM-012 CENTRE FOR ADVANCEMENT OF SCIENCE Dr. PRADEEP KUMAR T. 8-43-31, 3 CROSS ROAD H. NO. XII/ 170 VIDHYANAGAR ‘THE PALMS’ ANDHRA UNIVERSITY PO VAZHAKKALA, KAKKANAD PO. KOCHI-682030 VISHAKAPATNAM- 530003 PH:0484 2424911 EMAIL: [email protected] EMAIL:[email protected]
LM-006 LM-013 Dr. SHYAM KISHORE SRIVASTAVA Sri. R.V SUBBA RAO N.P.O.L, THRIKKAKARA PO, N.P.O.L,THRIKKAKARA P.O, KOCHI-682021 KOCHI-682021 MOB: 9447166315 PH:0484 2424911 EMAIL: [email protected] EMAIL:[email protected]
Ocean Society of India 131 LM-014 LM-022 Dr. P. A MAHESWARAN Sri. RAMESH P PAI N.P.O.L,THRIKKAKARA P.O, CC 8/15711A KOCHI-682021 POOMARAM HOUSE MOB:9846651296 ALATHUKUTTY ROAD EMAIL:[email protected] KOCHI-682002 MOB: 9446382544 LM-015 EMAIL: [email protected] Sri. ANIL KUMAR K. N.P.O.L, THRIKKAKARA PO, LM-023 KOCHI-682021 Dr K.V SANIL KUMAR MOB: 09846203991 N.P.O.L, THRIKKAKARA P.O, EMAIL:[email protected] KOCHI-682021 MOB: 9447100166 LM-016 EMAIL: [email protected] Dr. N MOHAN KUMAR N.P.O.L, THRIKKAKARA P.O, LM-024 KOCHI-682021 Dr. M.R RAMESH KUMAR PH:0484 244911 P.O.D, NIO DONA PAULA, GOA-4030041 LM-017 MOB: 9423056323 Sri. SANJEEV NAITHANI EMAIL: [email protected] N.P.O.L, THRIKKAKARA P.O, KOCHI-682021 LM-025 PH:0484 2424911 Dr. DODLA VENKATA BHASKARRAO DEPT. OF METEOROLOGY AND LM-018 OCEANOGRAPHY Dr. R.S RAJESH ANDHRA UNIVERSITY GEOPHYSICS DEPT VISHAKAPATNAM-53003 MOB: 9440592410 IIT, KHARAGPUR EMAIL:[email protected] KHARAGPUR-721302 EMAIL:[email protected] LM-026 Dr. A S UNNIKRISHNAN LM-019 N.I.O, DONA PAULA, Sri. CHANCHAL DE, GOA-403004 G-FAST PH: 08322450311 DRDO Hqrs, EMAIL: [email protected] New Delhi LM-027 LM-020 Dr. D.D EBENEZER Dr. BASIL MATHEW N.P.O.L, N.P.O.L, THRIKKAKARA P.O, THRIKKAKARA PO, KOCHI-682021 KOCHI-682021 PH:0484 2422590 EMAIL: [email protected]
LM-021 LM-028 Dr. K.P.B MOOSAD Sri M GOPAKUMAR N.P.O.L, THRIKKAKARA P.O, N.P.O.L, KOCHI-682021 THRIKKAKARA P.O, MOB: 9446401168 KOCHI-682021 EMAIL: [email protected] PH:0484 2424911
132 Ocean Society of India OSICON Proceedings 13-15 July 2011
LM-029 LM-035 Sri SUBASH CHANDRA BOSE M.R Sri VIBIN M.V NO. XXII/ 229, HARIGOVINDAM N.P.O.L, THRIKKAKARA PO, 14TH CROSS ROAD KOCHI-682021 MAVELINAGAR PH: 0484 2424911 CUSAT PO LM-036 KOCHI-682022 Sri M RAJENDRAN EMAIL:[email protected] 76, TYPE III, NPOL QUARTERS LM-030 THRIKKAKARA Dr R RAMESH KOCHI-682021 N.P.O.L, MOB:9447475597 EMAIL:[email protected] THRIKKAKARA P.O, KOCHI-682021 LM-037 PH:0484 2424911 Dr. M HARIKRISHNAN N.P.O.L, THRIKKAKARA P.O, LM-031 KOCHI-682021 Sri N SADHISH KUMAR MOB: 9447986162 KAILAS HOUSE KARINAKKAD LM-038 BEHIND VIMALA HOSTEL Sri. M M MUNI THRIKKAKARA PO, N.P.O.L, THRIKKAKARA PO, KOCHI-21 KOCHI-682021 PH:0484 2424911 PH:0484-2572624 EMAIL:[email protected] LM-032 Sri VIJAYAN PILLAI M. K. LM-039 N.P.O.L, THRIKKAKARA P.O, Sri. JINEESH GEORGE KOCHI-682021 N.P.O.L, THRIKKAKARA PO, MOB: 9447237090 KOCHI-682021 EMAIL: [email protected] MOB: 9447627027
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LM-034 LM-041 Sri D. THOMAS Dr. M.R SANTHA DEVI TYPE IV/34, SAGAR COMPLEX KOCHUPARAMBIL NPOL QUARTERS WEST END ENCLAVE THRIKKAKARA PO NGO FLAT ROAD, THRIKKAKARA KOCHI-682021 KOCHI-682021 MOB: 9447510362 MOB: 9895645696 EMAIL: [email protected] EMAIL: [email protected]
Ocean Society of India 133 LM-042 LM-048 Dr ABHIJIT SARKAR Dr. R SUNDARAVADIVELU OCEAN SCIENCES DIVISION MOG DEPT OF OCEAN ENGINEERING IIT SPACE APPLICATIONS CENTRE, MADRAS AHMEDABAD-380015 CHENNAI-600036 MOB: 9426301523 MOB: 9444008620 EMAIL: [email protected] EMAIL:[email protected]
LM-043 LM-049 Dr. S K BASU Dr. V ANANTHA SUBRAMANIAN OCEAN SCIENCES DIVISION MOG DEPT OF OCEAN ENGINEERING IIT SPACE APPLICATIONS CENTRE, MADRAS AHMEDABAD-380015 CHENNAI-600036 PH: 0792 6916115 MOB: 9444406812 EMAIL:[email protected] EMAIL: [email protected] LM-050 LM-044 Dr. S A SANNASIRAJ Dr. PRANAV SURESH DESAI DEPT OF OCEAN ENGINEERING IIT A-46 SHREE RANG VILLA MADRAS VASTRAPUR, CHENNAI-600036 NEAR RJT COLLEGE MOB: 9444032005 AHMEDABAD-380015 EMAIL: [email protected] MOB: 9824006712 LM-051 LM-045 Dr .K MURALI Dr. A UNNIKRISHNAN DEPT OF OCEAN ENGINEERING IIT N.P.O.L, THRIKKAKARA P.O, MADRAS KOCHI-682021 CHENNAI-600036 PH: 0484 2428067 MOB: 9444008627 EMAIL: [email protected] LM-046 Dr. K.V.S.R PRASAD LM-052 DEPT. OF METEOROLOGY AND Dr. S NALLAYARASU OCEANOGRAPHY DEPT OF OCEAN ENGINEERING IIT ANDHRA UNIVERSITY MADRAS VISHAKAPATNAM-53003 CHENNAI-600036 MOB: 9849798068 MOB: 9840742720 EMAIL: [email protected] EMAIL: [email protected]
LM-047 LM-053 Dr. Ing E.h. Dr. V SUNDAR Dr. P KRISHNANKUTTY DEPT OF OCEAN ENGINEERING IIT DEPT OF OCEAN ENGINEERING IIT MADRAS MADRAS CHENNAI-600036 CHENNAI-600036 MOB: 9444049629 PH: 0442 2574820 EMAIL: [email protected] EMAIL: [email protected]
134 Ocean Society of India OSICON Proceedings 13-15 July 2011
LM-054 CENTRAL UNIVERSITY P.O Dr. R PANNEER SELVAM GOCHIBOWLI DEPT OF OCEAN ENGINEERING IIT HYDRABAD - 500046 MADRAS MOB: 99896 25346 CHENNAI-600036 EMAIL: [email protected] MOB: 9884732776 LM-060 EMAIL: [email protected] Dr. DEBABRATA SEN DEPT OF OCEAN ENGINEERING & NAVAL LM-055 ARCHITECTURE Dr. A D RAO IIT, CENTER FOR ATMOSPHERIC SCIENCES KHARAGPUR-721302 IIT –DELHI MOB: 9434017359 HOUZKHAS EMAIL: [email protected] NEW DELHI-110016 MOB: 09868773650 LM-061 EMAIL: [email protected] Dr. C K RAJAN RAJAGEETAM MATHAR NAGAR LM-056 KOCHI-682033 Dr. P V JOSEPH MOB: 9847968699 DEPT OF ATMOSPHERIC SCIENCES EMAIL: [email protected] CUSAT LM-062 FINE ARTS AVENUE Dr. RAMA GOVINADARAJAN KOCHI-682016 J NEHRU CENTRE FOR ADVANCED MOB: 9847625788 SCIENTIFIC RESEARCH EMAIL: [email protected] JAKKUR. BANGLORE-560064 PH:0802 2082828E LM-057 MAIL: [email protected] Dr. R SAJEEV SAUPARNIKA LM-063 YMJ ROAD Dr. K.R SRINIVAS NORTH JANATHA J NEHRU CENTRE FOR PALARIVATTOM ADVANCEDSCIENTIFIC RESEARCH KOCHI_682025 JAKKUR, BANGLORE-560064 EMAIL: [email protected] PH: 080 22082836 EMAIL: [email protected] LM-058 Dr. THOMAS MATHEW LM-064 Dr. M R BOOPENDRANATH A-24, CHANDOLODIA KAILASNAGAR CENTRE INSTOTUTE OF FISHERIES CO. OP. HOUSING SOCIETY LTD TECHNOLOGY Dr. SHILPA SHILPA BHUVAN PO MATSYAPURI CHANDOLODIA KOCHI-682029 AHMADABAD – 382481 MOB: 9447665875E MOB: 09427069018 MAIL:[email protected] EMAIL:[email protected] LM-065 LM-059 Dr. DEBASIS SENGUPTA Dr A C NARAYANA CAOS PROFESSOR IISc, BANGLORE-560012 CENTRE FOR EARTH SPACE SCIENCE PH: 0802 2933066 UNIVERSITY OF HYDRABAD EMAIL: [email protected]
Ocean Society of India 135 LM-066 LM-073 Dr. DEBASIS KUMAR MAHAPATRA Dr. RAJAT ROY CHAUDHURY CAS, IIT DELHI NIOT HAUZKHAS VELACHERY NEWDELHI-110016 TAMBARAM ROAD MOB: 9818306164 PALLIKARANAI EMAIL: [email protected] CHENNAI-600100 EMAIL: [email protected] LM-067 LM-074 Dr. G S BHAT Sri. K.M SIVAKHOLUNDU CAOS NIOT, PALLIKARANAI IISc, BANGLORE CHENNAI-601302 PH: 0802 2933071 MOB: 9444399804 EMAIL: [email protected] EMAIL: [email protected]
LM-068 LM-075 Dr. SYED WAJIH AHMAD NAQVI Dr. BASANTA KUMAR JENA NIO NIOT CAMPUS VELACHERY DONA PAULA TAMBARAM ROAD, PH: 0832 2450294 PALLIKARANAI EMAIL: [email protected] CHENNAI-600100 MOB: 9444399850 LM-069 EMAIL: [email protected] Dr. ELGAR DESA NIO LM-076 DONA PAULA Dr. RAJKUMAR MOB: 9890444851 OCEAN SCIENCES DIVISION EMAIL: [email protected] METEOROLOGY & OCEANOGRAPHIC GROUP LM-070 SAC (ISRO), AHMEDABAD-380015 Dr. S. KATHRIROLI MOB: 9898575023 L&T, CHENNAI EMAIL: [email protected] MOB: 9444399800 LM-077 LM-071 CAPTAIN NVS RAJU INS ZAMORIN Dr. SHAILESH NAYAK NAVAL ACADEMY SECRETARY EZHIMALA MINISTRY OF EARTH SCIENCES RAMANTHALI PO GOVT. OF INDIA, NEW DELHI KANNUR-670308 MOB: 9441013377 MOB: 9496181551 EMAIL: [email protected] LM-072 Dr. S CHIDAMBARAM LM-078 DEPT OF EARTH SCIENCES Dr. ARUN CHAKRABORTY ANNAMALAI UNIVERSITY CORAL, IIT KHARAGPUR ANNAMALAI NAGAR KHARAGPUR-721302 MOB: 9842775874 MOB: 9733539295 EMAIL: [email protected] EMAIL: [email protected]
136 Ocean Society of India OSICON Proceedings 13-15 July 2011
LM-079 ANDHRA UNIVERSITY Dr. M. RAVICHANDRAN INCOIS VISHAKAPATNAM-530003 OCEAN VALLEY PO BOX NO. 21 IDA MOB: 9989191239 JEDIMETLA EMAIL: [email protected] HYDERABAD 55 MOB: 94471229296 LM-086 EMAIL: [email protected] Dr. PATURY RAJENDRA PRASAD DEPT OF GEOPHYSICS LM-080 ANDHRA UNIVERSITY Dr. K . AJITH JOSEPH VISHAKAPATNAM-530003 GOPAL RESIDENCY II FLOOR MOB: 9701155589 THOTTEKAT ROAD EMAIL: [email protected] KOCHI-682011 MOB: 09447325564 LM-087 EMAIL: [email protected] Dr. SUJATHA C. H DEPT OF CHEMICAL OCEANOGRAPHY LM-081 SCHOOL OF MARINE SCIENCES Dr. V.S.N MURTHY CUSAT, KOCHI-16 176 LAWSONS BAY COLONY MOB: 9995991778 VISHAKAPATNAM-530017 EMAIL: [email protected] MOB: 09951290356 EMAIL: [email protected] LM-088 DR.K.S.R.MURTHY LM-082 C S I R-EMIRITUS SCIENTIST RESHMI SHARMA SCIENTIST G3,RAVICHAKRA APARTMENT SPACE APPLICATION CENTRE J.R NAGAR INADIAN SPACE RESEARCH OLD VENKOJIPALEM ORGANOSATION VISHAKHAPATNAM AHMADABAD LM-089 LM-083 DR.PRASAD KUMAR BHASKARAN DR.SATHEESH CHANDRA SHENOI ASST PROFESSOR DIRECTOR IIT KHARAGPUR INCOIS, HYDERABAD MOB: 9932978842 [email protected] [email protected]
LM-084 LM-090 Dr. SATHYA NAIDU Dr. JAYA KUMAR SEELAM Prof EMERITUS NIO, DONA PAULA UNIVERSITY OF ALASKA GOA-403004 INSTITUTE OF MARINE SCIENCES PH: 2450316 FAIRBANKS, AK99775, U.S.A EMAIL: [email protected] MOB: 388-4041 EMAIL: [email protected] LM-091 Dr. N.P. KURIAN LM-085 HEAD MARINE SCIENCE DEVISION Dr. K GOPALA REDDY CETRE FOR EARTH SCIENCE STUDIES DEPT OF METEOROLOGY & TRIVANDRUM – 695031 OCEANOGRAPHY E-MAIL: [email protected]
Ocean Society of India 137 LM-092 LM-098 Dr. CHANDRAMADHAB PAL Dr. C. ANNAPURANA READER PROFESSOR DEPT. OF PHYSICS DEPT. OF ZOOLOGY RAMAKRISHNA MISSION VIDYAMADIRA ANDHRA UNIVERSITY BELURMATH VISHAKHAPATANAM- 53003 HOWRAH - 711202 E-MAIL: [email protected] E-mail: [email protected] LM-99 LM-093 Dr. C. KRISHNAIAH DR.G BHARATI PROFESSOR RESEARCH CO ORDINATOR DEPARTMENT OF METEROLOGY & OCEAN & ATMOSPHERIC SCIENCE AND OCEANOGRAPHY TECHNOLOGY CELL ANDHRA UNIVERSITY MANGALORE UNIVERSITY VISHAKAPATNAM-530017 MANGALA GANGOTRI – 574199 MOB-08912796080 E-MAIL: [email protected] [email protected] LM-100 LM-094 Dr. VIBHA SANDIAS SHARMA Dr. C. SHAJI SENIOR PROJECT ASSOCIATE ASSISTANT PROFESSOR INSTITUTE OF OCEAN MANAGEMENT CORAL ANNA UNIVERSITY IIT KHARAGPUR CHENNAI – 600025 KHARGAPUR -721302 E-MAIL: [email protected] EMAIL: [email protected] LM-101 LM-095 Dr. USHA NATESAN Dr. R. RAGHU PRAKASH SENIOR SCIENTIST PROFESSOR CIFT, OCEAN VIEW LAGENT CENTRE FOR ENVIRONMENTAL STUDIES VISHAKHAPATTANAM – 530003 ANNA UNIVERSITY EMAIL: [email protected] CHENNAI 600025 E-MAIL: [email protected] LM-096 Dr. SSV SIVARAMA KRISHNA LM-102 DEPARTMENT OF METEOROLOGY & Dr. K. RAVINDRAN OCEANOGRAPHY 49/ 172 –D ANDHRA UNIVERSITY CHITRANJALI VISHAKAPATTANAM BLOSSOM ROAD E-MAIL: [email protected] ELAMAKKARA LM-097 COCHIN – 682026 Dr. M.BABA E-MAIL: [email protected] BARKATH 14, BREEZE ENCLAVE LM-103 AKKULAM ROAD, ULLOOR DR. M.K. MUKUNDAN TRIVANDRUM-695011 PRICIPAL SCIENTIST PH: 0471-2550764 CIFT MOB. 95677 61403 COCHIN 29 EMAIL: [email protected] E-MAIL: [email protected]
138 Ocean Society of India OSICON Proceedings 13-15 July 2011
LM-104 LM-110 Dr. MARATHADU SUDHAKAR Dr. K. RAJITH ADVISOR / SCI g ICI- HOLY FAITH RESIDENCY MINISTRY OF EARTH SCIENCE THRIKAKARA BLOCK -12 KOCHI- 682021 CGO COMPLEX EMAIL: [email protected] LODHI ROAD NEW DELHI – 110003 LM-111 E-MAIL: [email protected] Dr. M.A. ATMANAND NIOT, VALANCHERY LM-105 THAMBARAM MAIN ROAD Dr. K.V. JAYACHANDRAN PALLIKARANAI, PROFESSOR CHENNAI – 600100 DEPT. OF FISHERY BIOLOGY EMAIL : [email protected] COLLEGE OF FISHEIRES KAU, COCHIN- 682506 LM-112 E-MAIL: [email protected] Dr. G.A. RAMADASS NIOT, VALANCHERY LM-106 THAMBARAM MAIN ROAD Dr. VINU K VALSALA PALLIKARANAI GOSAT, CRER, CHENNAI – 600100 NATIONAL INSTITUTE FOR EMAIL : [email protected] ENVIRONMENTAL STUDIES TSUKUBA, IBARAKI LM-113 JAPPAN -305-8506 Shri. VIJAYA RAVICHANDRAN E-MAIL: [email protected] COASTAL AND ENVIRONMENTAL LM-107 ENGG. DIV. Sri. DEBADATTA SWAIN NIOT, VALANCHERY SCIENTIST, OCEANOGRAPHIC THAMBARAM MAIN ROAD DEVISION(AS&OG) PALLIKARANAI NATIONAL REMOTE SENSING CENTRE CHENNAI – 600100 ISRO, BALANAGAR, HYDRABAD 500037 EMAIL : [email protected] TEL:- 040 23884576 LM-114 EMAIL: [email protected] Dr. S. MUTHU KRISHNA BABU LM-108 NIOT, VALANCHERY Dr. P. NAMMALWAR THAMBARAM MAIN ROAD FORMER PRICIPAL SCIENTIST (ICAR) PALLIKARANAI, CHENNAI – 600100 121/46, SECOND STREET EMAIL : [email protected] KAMARAJ AVENUE, JUSTICE RAMASWAMY ROAD, ADAYAR -600025 LM-115 EMAIL: [email protected] Sri. KARUNAKAR KINTADA COASTAL AND ENVIRONMENTAL LM-109 ENGG. DIV. Sr. I. O.R. NANDAGOPAN NIOT, VALANCHERY QTR 14, TYPE -5 THAMBARAM MAIN ROAD NPOL RESIDENTIAL COMPLEX PALLIKARANAI THRIKAKKARA, KOCHI – 682021 CHENNAI – 600100 EMAIL: [email protected] EMAIL : [email protected]
Ocean Society of India 139 LM-116 NIOT, VALANCHERY Dr. PURNIMA JALIHAL THAMBARAM MAIN ROAD GROUP HEAD – EFW / DESALINATION PALLIKARANAI, CHENNAI – 600100 NIOT, VALANCHERY EMAIL : [email protected] THAMBARAM MAIN ROAD PALLIKARANAI, CHENNAI – 600100 LM-123 EMAIL : [email protected] A.N. SUBRAMANIAN SUNMERSIBLES &GAS HYDRATES LM-117 NIOT, VALANCHERY Dr. S. RAMESH THAMBARAM MAIN ROAD NIOT, VALANCHERY PALLIKARANAI, CHENNAI – 600100 THAMBARAM MAIN ROAD EMAIL : [email protected] PALLIKARANAI, CHENNAI – 600100 EMAIL : [email protected] LM-124 LM-118 Dr. G. LATHA Dr. S. SUNDARARAJAN OCEAN ACOUSTICS & MODELLING GROUP COASTAL AND ENVIRONMENTAL ENGG. NIOT, VALANCHERY NIOT, VALANCHERY THAMBARAM MAIN ROAD THAMBARAM MAIN ROAD PALLIKARANAI, CHENNAI – 600100 PALLIKARANAI, CHENNAI – 600100 EMAIL : [email protected] EMAIL : [email protected] LM-125 LM-119 Dr. G.VEMKATESAN K. AMUTHA NIOT, VALANCHERY DEEP SEA TECHNOLOGIES THAMBARAM MAIN ROAD NIOT, VALANCHERY PALLIKARANAI, CHENNAI – 600100 THAMBARAM MAIN ROAD EMAIL : [email protected] PALLIKARANAI, CHENNAI – 600100 EMAIL : [email protected] LM-126 Dr. M. KALYANI LM-120 NIOT, VALANCHERY N. RAVI ALIYAS GURUSWAMY THAMBARAM MAIN ROAD VESSEL MANAGEMENT CELL PALLIKARANAI, CHENNAI – 600100 NIOT, VALANCHERY THAMBARAM MAIN ROAD EMAIL : [email protected] PALLIKARANAI, CHENNAI – 600100 LM- 127 EMAIL : [email protected] PRANESH. S.B LM-121 NIOT, VALANCHERY M.SHANKAR THAMBARAM MAIN ROAD VESSEL MANAGEMENT CELL PALLIKARANAI, CHENNAI – 600100 NIOT, VALANCHERY EMAIL : [email protected] THAMBARAM MAIN ROAD PALLIKARANAI, CHENNAI – 600100 LM- 128 EMAIL : [email protected] Dr. J. MANECIUS SELVA KUMAR NIOT, VALANCHERY LM-122 THAMBARAM MAIN ROAD P. MURUGESH PALLIKARANAI, CHENNAI – 600100 OCEAN OBSERVATION SYSTEM EMAIL : [email protected]
140 Ocean Society of India OSICON Proceedings 13-15 July 2011
LM-129 LM- 135 V. SUSEENTHARAN PSV JAGADEESH CEE GROUP SCIENTIST NIOT, VALANCHERY NPOL, THRIKKAKARA THAMBARAM MAIN ROAD KOCHI 21 PALLIKARANAI EMAIL: [email protected] CHENNAI – 600100 EMAIL : [email protected] LM- 136 Dr. ROSAMMA STEPHEN LM-130 SCIENTIST F Dr. PRINCE PRAKASH JEBA KUMAR.J AJANTHA COASTAL AND ENVIRONMENTAL KALOOR – KADAVANTHRA ROAD ENGG. DIV., NIOT, VALANCHERY KOCHI - 682017 THAMBARAM MAIN ROAD LM 137 PALLIKARANAI Dr. V.V. GOPALAKRISHNA CHENNAI – 600100 SCIENTIST EMAIL : [email protected] PHISICAL OCEANOGRAPHIC DEVISION LM131 NIO, DONA PAULA Dr. T. SUNIL GOA - 403004 SCIENTIST D LM 138 NPOL Dr.P.M. MURALEEDHARAN KOCHI 21 SCIENTIST F LM-132 PHISICAL OCEANOGRAPHIC DEVISION NIO, DONA PAULA DOMONIC RICKY FERNANDEZ GOA - 403004 SCIENTIST C NPOL LM 139 KOCHI 21 Mr. SURA APPALA NAIDU EMAIL: [email protected] PROJECT ASSISTANT NIO, REGIONAL CENTRE LM-133 8-44-1/5,PLOT NO : 94 DR.K.MOHANKUMAR CHINNA WALTAIR, PROFESSOR VISHAKAPATNAM- 530003 DEPARTMENT OF ATMOSPHERIC SCIENCE CUSAT LM 140 LAKE SIDE CAMPUS, FINE ARTS AVENUE Dr. K. SUDARSAN COCHIN 16 GROUP HEAD (ENGG. EMAIL :- [email protected] SCIENTIST F POL, THRIKKAKARA POST LM-134 KOCHI-21 DR.TATASUDHAKAR SCIENTIST E LM 141 NIOT Mr. PADMANABHAM MADATHALA PALLIKARANAI SCIENTIST CHENNAI – 600100 NPOL, THRIKKAKARA POST EMAIL: [email protected] KOCHI-21
Ocean Society of India 141 “The Wave Glider: a wave powered autonomous surface vehicle for operational & predictive oceanography” Neil Trenaman Vice President of International Business Development, Liquid Robotics, Inc.
The Wave Glider wave-powered unmanned maritime vehicle (UMV), represents a novel and unique approach to persistent ocean presence. Wave Gliders harvest the abundant energy contained in ocean waves to provide essentially limitless propulsion while two solar panels continuously replenish batteries that are used to power the vehicle’s control electronics, communications systems, and payloads. Wave Glider is a hybrid sea-surface and underwater vehicle in that it is comprised of a submerged “glider” attached via a tether to a surface float.
The Wave Glider is well suited for air-sea surface investigations. With a continuous view of the sky the vehicle makes use of GPS for precise navigation and iridium, or other RF communications, for command and control. The Wave Glider can operate as a vessel, covering long distances in the ocean, or as a station-keeping platform. Test results, to be included in this presentation, will discuss both roles.
In this presentation, we review the design of this platform and present results from the extensive engineering sea trials conducted with prototype and production versions of the vehicle. The vehicle’s performance in a variety of ocean conditions — varying sea state, wind speed, and surface currents — is discussed. Differing wind and wave conditions yield varying performance of the Wave Glider. Field experience and analytical results will be presented. While each situation is unique experience indicates the Wave Glider can achieve an average speed of 1.5 knots.
In addition to the basic Wave Glider technology we will focus on the role of currents in the operation of the vehicle and as an application. Liquid Robotics operators have become familiar with a variety of ocean environments including the Pacific Ocean between Hawaii and California and the Gulf of Mexico. Field experience will be discussed. Recent projects have explored the Wave Glider’s ability to enter a “drifter” mode by entering a locked turn. Preliminary assessments of this approach will be presented.
The Wave Glider is also able to carry a water speed sensor for the evaluation of relative velocity through the water. Combined with GPS measurements of velocity relative to the earth the immediate surface current may be derived. An analysis of this technique will be presented. Finally this presentation will discuss the integration of an acoustic Doppler current profiler (ADCP) on the Wave Glider. The technical implementation and preliminary data results will be described. OCEAN SOCIETY OF INDIA (Regn No: ER 360/06) c/o Regional Centre, National Institute of Oceanography Post Box No: 1913, Dr. Salim Ali Road, Kochi - 682018 www.oceansociety.in [email protected]
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