SIO 210: Physical Properties of Seawater II Outline 9
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Fronts in the World Ocean's Large Marine Ecosystems. ICES CM 2007
- 1 - This paper can be freely cited without prior reference to the authors International Council ICES CM 2007/D:21 for the Exploration Theme Session D: Comparative Marine Ecosystem of the Sea (ICES) Structure and Function: Descriptors and Characteristics Fronts in the World Ocean’s Large Marine Ecosystems Igor M. Belkin and Peter C. Cornillon Abstract. Oceanic fronts shape marine ecosystems; therefore front mapping and characterization is one of the most important aspects of physical oceanography. Here we report on the first effort to map and describe all major fronts in the World Ocean’s Large Marine Ecosystems (LMEs). Apart from a geographical review, these fronts are classified according to their origin and physical mechanisms that maintain them. This first-ever zero-order pattern of the LME fronts is based on a unique global frontal data base assembled at the University of Rhode Island. Thermal fronts were automatically derived from 12 years (1985-1996) of twice-daily satellite 9-km resolution global AVHRR SST fields with the Cayula-Cornillon front detection algorithm. These frontal maps serve as guidance in using hydrographic data to explore subsurface thermohaline fronts, whose surface thermal signatures have been mapped from space. Our most recent study of chlorophyll fronts in the Northwest Atlantic from high-resolution 1-km data (Belkin and O’Reilly, 2007) revealed a close spatial association between chlorophyll fronts and SST fronts, suggesting causative links between these two types of fronts. Keywords: Fronts; Large Marine Ecosystems; World Ocean; sea surface temperature. Igor M. Belkin: Graduate School of Oceanography, University of Rhode Island, 215 South Ferry Road, Narragansett, Rhode Island 02882, USA [tel.: +1 401 874 6533, fax: +1 874 6728, email: [email protected]]. -
A Destabilizing Thermohaline Circulation–Atmosphere–Sea Ice
642 JOURNAL OF CLIMATE VOLUME 12 NOTES AND CORRESPONDENCE A Destabilizing Thermohaline Circulation±Atmosphere±Sea Ice Feedback STEVEN R. JAYNE MIT±WHOI Joint Program in Oceanography, Woods Hole Oceanographic Institution, Woods Hole, Massachusetts JOCHEM MAROTZKE Center for Global Change Science, Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts 18 November 1996 and 9 March 1998 ABSTRACT Some of the interactions and feedbacks between the atmosphere, thermohaline circulation, and sea ice are illustrated using a simple process model. A simpli®ed version of the annual-mean coupled ocean±atmosphere box model of Nakamura, Stone, and Marotzke is modi®ed to include a parameterization of sea ice. The model includes the thermodynamic effects of sea ice and allows for variable coverage. It is found that the addition of sea ice introduces feedbacks that have a destabilizing in¯uence on the thermohaline circulation: Sea ice insulates the ocean from the atmosphere, creating colder air temperatures at high latitudes, which cause larger atmospheric eddy heat and moisture transports and weaker oceanic heat transports. These in turn lead to thicker ice coverage and hence establish a positive feedback. The results indicate that generally in colder climates, the presence of sea ice may lead to a signi®cant destabilization of the thermohaline circulation. Brine rejection by sea ice plays no important role in this model's dynamics. The net destabilizing effect of sea ice in this model is the result of two positive feedbacks and one negative feedback and is shown to be model dependent. To date, the destabilizing feedback between atmospheric and oceanic heat ¯uxes, mediated by sea ice, has largely been neglected in conceptual studies of thermohaline circulation stability, but it warrants further investigation in more realistic models. -
Lagrangian Measurement of Subsurface Poleward Flow Between 38 Degrees N and 43 Degrees N Along the West Coast of the United States During Summer, 1993
CORE Metadata, citation and similar papers at core.ac.uk Provided by Calhoun, Institutional Archive of the Naval Postgraduate School Calhoun: The NPS Institutional Archive Faculty and Researcher Publications Faculty and Researcher Publications 1996-09-01 Lagrangian Measurement of subsurface poleward Flow between 38 degrees N and 43 degrees N along the West Coast of the United States during Summer, 1993 Collins, Curtis A. Geophysical Research Letters, Vol. 23, No. 18, pp. 2461-2464, September 1, 1996 http://hdl.handle.net/10945/45730 GEOPHYSICAL RESEARCH LETTERS, VOL. 23, NO. 18, PAGES 2461-2464, SEPTEMBER 1, 1996 Lagrangian Measurement of subsurface poleward Flow between 38øN and 43øN along the West Coast of the United States during Summer, 1993 CurtisA. Collins,Newell Garfield, Robert G. Paquette,and Everett Carter 1 Departmentof Oceanography,Naval Postgraduate School, Monterey, California Abstract. SubsurfaceLagrangian measurementsat about Undercurrentalong the coastsof California and Oregon. We 140 m showedthat the pathof the CaliforniaUndercurrent lay are using quasi-isobaric(float depth controlled primarily by next to the continentalslope betweenSan Francisco(37.80N) the pressureeffect on density)RAFOS floats (Rossby et al., and St. GeorgeReef (41.8øN) duringmid-summer 1993. The 1986) to make these measurements. A RAFOS float consists meanspeed along this 500 km pathwas 8 cms-1. Theflow at of a hydrophonemounted in a glasstube that is about2 meters this depth was not disturbedby upwelling centersat Point long. These hydrophonesreceive signals from three sound Reyesor CapeMendocino. Restfits also demonstratethe abil- sources that were moored 400 km offshore between 34.3øN and ity to acousticallytrack floats located well above the sound 40.4øN.The sound sources emit 15 W, 80 s signalsa•t 260 Hz channelaxis along the California coast. -
University Microfilms, Inc., Ann Arbor, Michigan the SYNTHESIS of POINT DATA
This dissertation has been microfilmed exactly as received 68-16,949 JOHNSON, Rockne Hart, 1930- THE SYNTHESIS OF POINT DATA AND PATH DATA IN ESTIMATING SOFAR SPEED. University of Hawaii, Ph.D., 1968 Geophysics University Microfilms, Inc., Ann Arbor, Michigan THE SYNTHESIS OF POINT DATA AND PATH DATA IN ESTIMATING SOFAR SPEED A DISSERTATION SUBMITTED TO THE GRADUATE DIVISION OF THE UNIVERSITY OF HAWAII IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY IN GEOSCIENCES June 1968 By Rockne Hart Johnson Dissertation Committee: William M. Adams, Chairman Doak C. Cox George H. Sutton George P. Woollard Klaus Wyrtki ii P~F~E Geophysical interest in the deep ocean sound (sofar) channel centers on its use as a tool for the detection and location of remote events. Its potential application to oceanography may lie in the monitoring of variations of physical properties averaged over long paths by sofar travel-time measurements. As the accuracy of computed event locations is generally dependent on the accuracy of travel-time calculations, the spatial and temporal variation of sofar speed is a matter of fundamental interest. The author's interest in this problem has grown out of a practical need for such information for application to the problem of locating the sources of earthquake I waves and submarine volcanic sounds. Although an exten sive body of sound-speed data is available from hydrographic casts, considerably more precise measurements can be made of explosion travel times over long paths. This dissertation develops a novel procedure for analytically combining these two types of data to produce a functional description of the spatial variation of safar speed. -
Overview of the Impacts of Anthropogenic Underwater Sound in the Marine Environment
Overview of the impacts of anthropogenic underwater sound in the marine environment Biodiversity Series 2009 Overview of the impacts of anthropogenic underwater sound in the marine environment OSPAR Convention Convention OSPAR The Convention for the Protection of the La Convention pour la protection du milieu Marine Environment of the North-East Atlantic marin de l'Atlantique du Nord-Est, dite (the “OSPAR Convention”) was opened for Convention OSPAR, a été ouverte à la signature at the Ministerial Meeting of the signature à la réunion ministérielle des former Oslo and Paris Commissions in Paris anciennes Commissions d'Oslo et de Paris, on 22 September 1992. The Convention à Paris le 22 septembre 1992. La Convention entered into force on 25 March 1998. It has est entrée en vigueur le 25 mars 1998. been ratified by Belgium, Denmark, Finland, La Convention a été ratifiée par l'Allemagne, France, Germany, Iceland, Ireland, la Belgique, le Danemark, la Finlande, Luxembourg, Netherlands, Norway, Portugal, la France, l’Irlande, l’Islande, le Luxembourg, Sweden, Switzerland and the United Kingdom la Norvège, les Pays-Bas, le Portugal, and approved by the European Community le Royaume-Uni de Grande Bretagne and Spain. et d’Irlande du Nord, la Suède et la Suisse et approuvée par la Communauté européenne et l’Espagne. 2 OSPAR Commission, 2009 Acknowledgements Author list (in alphabetical order) Thomas Götz Scottish Oceans Institute, East Sands University of St Andrews St Andrews, Fife KY16 8LB [email protected] Module 2, 8 Gordon Hastie SMRU Limited New Technology Centre North Haugh St Andrews, Fife KY16 9SR [email protected] Module 2, 8 Leila T. -
Glacial Ocean Circulation and Stratification Explained by Reduced
Glacial ocean circulation and stratification explained by reduced atmospheric temperature Malte F. Jansena,1 aDepartment of the Geophysical Sciences, The University of Chicago, Chicago, IL 60637 Edited by Mark H. Thiemens, University of California, San Diego, La Jolla, CA, and approved November 7, 2016 (received for review June 27, 2016) Earth’s climate has undergone dramatic shifts between glacial and We test the connection between atmospheric temperature interglacial time periods, with high-latitude temperature changes and ocean circulation and stratification changes, using idealized on the order of 5–10 ◦C. These climatic shifts have been asso- numerical simulations, which allow us to isolate the proposed ciated with major rearrangements in the deep ocean circulation mechanism. We use a coupled ocean–sea-ice model, with atmo- and stratification, which have likely played an important role in spheric temperature, winds, and evaporation–precipitation pre- the observed atmospheric carbon dioxide swings by affecting the scribed as boundary conditions (Materials and Methods). The partitioning of carbon between the atmosphere and the ocean. model uses an idealized continental configuration resembling the The mechanisms by which the deep ocean circulation changed, Atlantic and Southern Oceans, where the most elemental circu- however, are still unclear and represent a major challenge to our lation changes have been inferred (3, 5, 6, 12). understanding of glacial climates. This study shows that vari- ous inferred changes in the deep ocean circulation and stratifica- Results tion between glacial and interglacial climates can be interpreted We first focus on the model’s ability to reproduce key features as a direct consequence of atmospheric temperature differences. -
Ice Production in Ross Ice Shelf Polynyas During 2017–2018 from Sentinel–1 SAR Images
remote sensing Article Ice Production in Ross Ice Shelf Polynyas during 2017–2018 from Sentinel–1 SAR Images Liyun Dai 1,2, Hongjie Xie 2,3,* , Stephen F. Ackley 2,3 and Alberto M. Mestas-Nuñez 2,3 1 Key Laboratory of Remote Sensing of Gansu Province, Heihe Remote Sensing Experimental Research Station, Cold and Arid Regions Environmental and Engineering Research Institute, Chinese Academy of Sciences, Lanzhou 730000, China; [email protected] 2 Laboratory for Remote Sensing and Geoinformatics, Department of Geological Sciences, University of Texas at San Antonio, San Antonio, TX 78249, USA; [email protected] (S.F.A.); [email protected] (A.M.M.-N.) 3 Center for Advanced Measurements in Extreme Environments, University of Texas at San Antonio, San Antonio, TX 78249, USA * Correspondence: [email protected]; Tel.: +1-210-4585445 Received: 21 April 2020; Accepted: 5 May 2020; Published: 7 May 2020 Abstract: High sea ice production (SIP) generates high-salinity water, thus, influencing the global thermohaline circulation. Estimation from passive microwave data and heat flux models have indicated that the Ross Ice Shelf polynya (RISP) may be the highest SIP region in the Southern Oceans. However, the coarse spatial resolution of passive microwave data limited the accuracy of these estimates. The Sentinel-1 Synthetic Aperture Radar dataset with high spatial and temporal resolution provides an unprecedented opportunity to more accurately distinguish both polynya area/extent and occurrence. In this study, the SIPs of RISP and McMurdo Sound polynya (MSP) from 1 March–30 November 2017 and 2018 are calculated based on Sentinel-1 SAR data (for area/extent) and AMSR2 data (for ice thickness). -
Antarctic Sea Ice Control on Ocean Circulation in Present and Glacial Climates
Antarctic sea ice control on ocean circulation in present and glacial climates Raffaele Ferraria,1, Malte F. Jansenb, Jess F. Adkinsc, Andrea Burkec, Andrew L. Stewartc, and Andrew F. Thompsonc aDepartment of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139; bAtmospheric and Oceanic Sciences Program, Geophysical Fluid Dynamics Laboratory, Princeton, NJ 08544; and cDivision of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA 91125 Edited* by Edward A. Boyle, Massachusetts Institute of Technology, Cambridge, MA, and approved April 16, 2014 (received for review December 31, 2013) In the modern climate, the ocean below 2 km is mainly filled by waters possibly associated with an equatorward shift of the Southern sinking into the abyss around Antarctica and in the North Atlantic. Hemisphere westerlies (11–13), (ii) an increase in abyssal stratifi- Paleoproxies indicate that waters of North Atlantic origin were instead cation acting as a lid to deep carbon (14), (iii)anexpansionofseaice absent below 2 km at the Last Glacial Maximum, resulting in an that reduced the CO2 outgassing over the Southern Ocean (15), and expansion of the volume occupied by Antarctic origin waters. In this (iv) a reduction in the mixing between waters of Antarctic and Arctic study we show that this rearrangement of deep water masses is origin, which is a major leak of abyssal carbon in the modern climate dynamically linked to the expansion of summer sea ice around (16). Current understanding is that some combination of all of these Antarctica. A simple theory further suggests that these deep waters feedbacks, together with a reorganization of the biological and only came to the surface under sea ice, which insulated them from carbonate pumps, is required to explain the observed glacial drop in atmospheric forcing, and were weakly mixed with overlying waters, atmospheric CO2 (17). -
Acceleration in Acoustic Wave Propagation Modelling Using Openacc/Openmp and Its Hybrid for the Global Monitoring System
Acceleration in Acoustic Wave Propagation Modelling using OpenACC/OpenMP and its hybrid for the Global Monitoring System Noriyuki Kushida*1, Ying-Tsong Lin*2, Peter Nielsen*1, and Ronan Le Bras*1 *1 CTBTO Preparatory Commission for the Comprehensive Nuclear-Test-Ban Treaty Organization Provisional Technical Secretariat *2 Woods Hole Oceanographic Institution, USA Disclaimer: The views expressed herein are those of the author(s) and do not necessarily reflect the views of the CTBT Preparatory Commission. Background (Who we are) The CTBT (Comprehensive Nuclear-Test-Ban Treaty) bans all types of nuclear explosions. CTBTO operates a worldwide monitoring system to catch the signs of nuclear explosions with four technologies: Seismic Infrasound Hydroacoustic Radionuclide Atmospheric explosion Underground explosion Underwater explosion 2 Background (Underwater event and Hydroacoustic observation) ● Hydroacoustic: acoustic waves through the Ocean Seismometer Hydrophone Phase conversion Underwater explosion ● A big explosion in the Ocean can generate a sound wave ● We can catch such sounds with ○ microphones in the Ocean (hydrophone) ○ seismometers on the coast Photo/Video from CTBTO Website Background (Hydroacoustic stations in CTBTO) ● “H” icone: Hydrophone (H-phase). 6 stations ● “T” icone: Seismometer (T-phase). 4 stations ● Hydroacoustic waves can travel very long distances ○ Complex phenomena can be involved ● Seismic stations; 170 (50 primary + 120 auxiliary) to cover the globe An example: Argentinian submarine ARA San Juan 1/3 Last Contact -
DESALINATION: Balancing the Socioeconomic Benefits and Environmental Costs
DESALINATION: Balancing the Socioeconomic Benefits and Environmental Costs www.research.natixis.com https://gsh.cib.natixis.com executive summary Chapter 1 Making sense of desalination: technological, financial and economic aspects of desalination assets Chapter 2 Sustainability assessment of desalination assets: recognizing the socioeconomic benefits and mitigating environmental costs of desalination Chapter 3 Desalination sustainability performance scorecard acknowledgements appendix biblioghraphy TABLE OF CONTENTS OF TABLE 1. Making sense of desalination: technological, financial and economic aspects of desalination assets 1. DESALINATION TECHNOLOGIES 2. FINANCIAL AND ECONOMIC ASPECTS OF DESALINATION ASSETS 1.1. AN OVERVIEW OF DESALINATION TECHNOLOGIES 2.1.THE DEVELOPMENT AND FINANCING OF DESALINATION ASSETS Thermal desalination: Multistage Flash Distillation and Multieffect Distillation Building and operating desalination assets: complex and evolving value chain Membrane desalination: Reverse Osmosis Project development models: fine-tuning Hybridization of thermal and the appropriate risk-sharing model membrane desalination Bringing capital to desalination assets: A set of parameters to assess the performance an increasingly strategic issue and efficiency of desalination assets Case study of desalination in Israel: innovative 1.2. A BRIEF HISTORY AND financing schemes achieving some of the GEOGRAPHICAL DISTRIBUTION OF lowest desalinated water costs worldwide DESALINATION TECHNOLOGIES Case study of desalination in Singapore: The market -
Rapid Mixing and Exchange of Deep-Ocean Waters in an Abyssal Boundary Current
Rapid mixing and exchange of deep-ocean waters in an abyssal boundary current Alberto C. Naveira Garabatoa,1, Eleanor E. Frajka-Williamsb, Carl P. Spingysa, Sonya Leggc, Kurt L. Polzind, Alexander Forryana, E. Povl Abrahamsene, Christian E. Buckinghame, Stephen M. Griffiesc, Stephen D. McPhailb, Keith W. Nichollse, Leif N. Thomasf, and Michael P. Meredithe aOcean and Earth Science, National Oceanography Centre, University of Southampton, SO14 3ZH Southampton, United Kingdom; bNational Oceanography Centre, SO14 3ZH Southampton, United Kingdom; cNational Oceanic and Atmospheric Administration Geophysical Fluid Dynamics Laboratory & Atmospheric and Oceanic Sciences Program, Princeton University, Princeton, NJ 08544; dDepartment of Physical Oceanography, Woods Hole Oceanographic Institution, Woods Hole, MA 02543; ePolar Oceans, British Antarctic Survey, CB3 0ET Cambridge, United Kingdom; and fDepartment of Earth System Science, Stanford University, Stanford, CA 94305 Edited by Eric Guilyardi, Laboratoire d’Océanographie et du Climat: Expérimentations et Approches Numériques, Institute Pierre Simon Laplace, Paris, France, and accepted by Editorial Board Member Jean Jouzel May 26, 2019 (received for review March 8, 2019) The overturning circulation of the global ocean is critically shaped UK–US Dynamics of the Orkney Passage Outflow (DynOPO) by deep-ocean mixing, which transforms cold waters sinking at high project (17), and consisted of two core elements: a series of fifteen latitudes into warmer, shallower waters. The effectiveness of mixing 6- to 128-km-long vessel-based sections of profile measurements in driving this transformation is jointly set by two factors: the crossing the boundary current at an unusually high horizontal – – ∼ intensity of turbulence near topography and the rate at which well- resolution (Fig. -
Chapter 2 Approximate Thermodynamics
Chapter 2 Approximate Thermodynamics 2.1 Atmosphere Various texts (Byers 1965, Wallace and Hobbs 2006) provide elementary treatments of at- mospheric thermodynamics, while Iribarne and Godson (1981) and Emanuel (1994) present more advanced treatments. We provide only an approximate treatment which is accept- able for idealized calculations, but must be replaced by a more accurate representation if quantitative comparisons with the real world are desired. 2.1.1 Dry entropy In an atmosphere without moisture the ideal gas law for dry air is p = R T (2.1) ρ d where p is the pressure, ρ is the air density, T is the absolute temperature, and Rd = R/md, R being the universal gas constant and md the molecular weight of dry air. If moisture is present there are minor modications to this equation, which we ignore here. The dry entropy per unit mass of air is sd = Cp ln(T/TR) − Rd ln(p/pR) (2.2) where Cp is the mass (not molar) specic heat of dry air at constant pressure, TR is a constant reference temperature (say 300 K), and pR is a constant reference pressure (say 1000 hPa). Recall that the specic heats at constant pressure and volume (Cv) are related to the gas constant by Cp − Cv = Rd. (2.3) A variable related to the dry entropy is the potential temperature θ, which is dened Rd/Cp θ = TR exp(sd/Cp) = T (pR/p) . (2.4) The potential temperature is the temperature air would have if it were compressed or ex- panded (without condensation of water) in a reversible adiabatic fashion to the reference pressure pR.