Cyclone Warning in India Standard Operation Procedure July 2013 INDIA METEOROLOGICAL DEPARTMENT Ministry of Earth Sciences Govt. of India Cyclone Warning in India : Standard Operation Procedure A publication of: India Meteorological Department Ministry of Earth Sciences Government of India Mausam Bhawan Lodi Road New Delhi-110003 July, 2013 When citing these guidelines the following citation should be used: Cyclone Warning in India : Standard Operation Procedure Published by India Meteorological Department, Ministry of Earth Sciences, Government of India, Mausam Bhawan, Lodi Road, New Delhi-110003, SOP No. 10/2013, 200pp. Contents Page No. List of Figures ....................................................................................................... xi List of Tables ...................................................................................................... xv List of Acronyms .................................................................................................... xvii Preface ................................................................................................... xxiii Acknowledgements .................................................................................................... xxv 1 Introduction ........................................................................................................ 1 1.1. Classification of Cyclonic Disturbances .................................................................. 1 1.2. Structure of Tropical Cyclone ................................................................................. 2 1.2.1. Eye ........................................................................................................ 3 1.2.2. Wall Cloud Region or Eye Wall .................................................................. 3 1.2.3. Rain/Spiral Bands ....................................................................................... 4 1.2.4. Outer Storm Area ........................................................................................ 5 1.2.5. Vertical Structure ......................................................................................... 5 1.3. Life Cycle of Tropical Cyclone ................................................................................ 6 1.3.1 Formative Stage .......................................................................................... 7 1.3.2. Immature Stage ........................................................................................... 7 1.3.3. Mature Stage ............................................................................................... 7 1.3.4. Decaying Stage .......................................................................................... 8 1.4. Hazard due to Cyclone ........................................................................................... 8 1.4.1. Winds ...................................................................................................... 10 1.4.2. Marine Impact ............................................................................................ 13 1.4.3. Rainfall ...................................................................................................... 13 1.4.4. Storm Surge ............................................................................................... 14 iii CY C LONE WARNING IN INDIA - STANDARD OPERATION PRO C EDURE 1.5 Historical Cyclones and their Impact: ................................................................... 20 1.6. Climatology of Tropical Cyclones ........................................................................ 20 1.6.1. Frequency of Disturbances ....................................................................... 20 1.6.2. Location of Genesis ................................................................................... 20 1.6.3. Intensification ............................................................................................. 23 1.6.4. Movement ................................................................................................. 23 1.6.5. Landfall ..................................................................................................... 26 1.7. Naming of Cyclones .............................................................................................. 29 1.8. Early Warning System ........................................................................................... 30 2 Cyclone Warning Organisation ................................................................................. 32 2.1 Milestones ...................................................................................................... 32 2.2. Organizational Structure ........................................................................................ 34 2.2.1. Regional Specialized Meteorological Centre (RSMC)- Tropical Cyclones, New Delhi ................................................................... 34 2.2.2. Cyclone Warning Division ......................................................................... 36 2.2.3. ACWCs/CWCs .......................................................................................... 36 2.2.4. Other Offices ............................................................................................ 37 3 Needs for Monitoring and Prediction ....................................................................... 39 3.1. Data and Products ................................................................................................ 39 3.2. Intensive Observational Phases (IOP) ................................................................. 44 3.3. Manpower Needed ................................................................................................ 45 4 Observational Aspects of Cyclone Warning System ............................................. 46 4.1. Introduction ...................................................................................................... 46 4.2. Surface (Land, Ocean) Based Observations ....................................................... 47 4.2.1. Land Based Conventional Surface Observatories ................................... 48 4.2.2. Cooperative Cyclone Reporting Network of Stations ............................... 49 4.2.3. Time of Observations ................................................................................ 49 iv CONTENT S 4.3. Ship Observations ................................................................................................. 50 4.3.1. Voluntary Observing Fleet (VOF) .............................................................. 50 4.3.2. Recording and Reporting of Ship Observations ...................................... 50 4.4. Data Buoy Network ............................................................................................... 51 4.5. Tide Gauges ...................................................................................................... 52 4.6. Reports from Airport Meteorological Offices ........................................................ 52 4.7. Special Observations from Coastal Stations ........................................................ 54 4.7.1. Need for Special Observations ................................................................. 54 4.7.2. General Instructions ................................................................................... 54 4.7.3. Discretion of Storm Warning Officer ......................................................... 55 4.7.4. Role of Special Observations in Determining the Period of Landfall ..... 55 4.7.5 Importance of 24 hr Pressure Change (P24P24) ....................................... 55 4.7.6. Discontinuance of Special Observations .................................................. 55 4.8. Automatic Weather Stations .................................................................................. 56 4.9. Upper Air Observations ........................................................................................... 57 4.9.1. Pilot Balloon Observatories ........................................................................ 57 4.9.2. Radiosonde/Radiowind Observations ...................................................... 57 4.9.3. Wind Profilers ............................................................................................ 58 4.10. Microseism Observations ...................................................................................... 60 4.11. Quality Control of Observations ............................................................................ 60 4.12. Radar Observations ............................................................................................... 61 4.12.1. Tracking by S-band Radars and Doppler Radars ................................... 61 4.12.2. Radars in Neighbouring Countries ............................................................ 65 4.12.3. X-Band Radars.......................................................................................... 65 4.12.4. Operation of Radar and Availability of Radar Observations ................. 66 4.12.5. Radar Bulletin .......................................................................................... 67 4.13. Satellite Cloud Imagery Data and Derived Products Useful in Cyclone Warning ................................................................................................... 67 v CY C LONE WARNING IN INDIA - STANDARD OPERATION PRO C EDURE 4.13.1. Cloud Imagery Data .................................................................................