DOCSLIB.ORG

Arctic and N-Atlantic High-Resolution Ocean and Sea-Ice Model

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Arctic and N-Atlantic High-Resolution Ocean and Sea-Ice Model Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Geosci. Model Dev. Discuss., 8, 1–52, 2015 www.geosci-model-dev-discuss.net/8/1/2015/ doi:10.5194/gmdd-8-1-2015 GMDD © Author(s) 2015. CC Attribution 3.0 License. 8, 1–52, 2015 This discussion paper is/has been under review for the journal Geoscientific Model Arctic and N-Atlantic Development (GMD). Please refer to the corresponding final paper in GMD if available. high-resolution ocean and sea-ice A high-resolution ocean and sea-ice model modelling system for the Arctic and North F. Dupont et al. Atlantic Oceans Title Page 1 3 4 3 2 2 F. Dupont , S. Higginson , R. Bourdallé-Badie , Y. Lu , F. Roy , G. C. Smith , Abstract Introduction J.-F. Lemieux2, G. Garric4, and F. Davidson5 Conclusions References 1MSC, Environment Canada, Dorval, QC, Canada 2MRD, Environment Canada, Dorval, QC, Canada Tables Figures 3Bedford Institute of Oceanography, Fisheries & Oceans Canada, Dartmouth, NS, Canada 4 Mercator-Océan, Toulouse, France J I 5Northwest Atlantic Fisheries Centre, Fisheries and Oceans Canada, St. John’s, NF, Canada J I Received: 18 November 2014 – Accepted: 5 December 2014 – Published: 5 January 2015 Back Close Correspondence to: F. Dupont ([email protected]) Full Screen / Esc Published by Copernicus Publications on behalf of the European Geosciences Union. Printer-friendly Version Interactive Discussion 1 Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Abstract GMDD As part of the CONCEPTS (Canadian Operational Network of Coupled Environmental PredicTion Systems) initiative, The Government of Canada is developing a high res- 8, 1–52, 2015 olution (1=12◦) ice–ocean regional model covering the North Atlantic and the Arctic 5 oceans. The objective is to provide Canada with short-term ice–ocean predictions and Arctic and N-Atlantic hazard warnings in ice infested regions. To evaluate the modelling component (as op- high-resolution posed to the analysis – or data-assimilation – component), a series of hindcasts for ocean and sea-ice the period 2003–2009 is carried out, forced at the surface by the Canadian Global Re- model Forecasts. These hindcasts test how the model represent upper ocean characteristics 10 and ice cover. Each hindcast implements a new aspect of the modelling or the ice– F. Dupont et al. ocean coupling. Notably, the coupling to the multi-category ice model CICE is tested. The hindcast solutions are then assessed using a validation package under develop- ment, including in-situ and satellite ice and ocean observations. The conclusions are: Title Page (1) the model reproduces reasonably well the time mean, variance and skewness of Abstract Introduction 15 sea surface height. (2) The model biases in temperature and salinity show that while the mean properties follow expectations, the Pacific Water signature in the Beaufort Conclusions References Sea is weaker than observed. (3) However, the modelled freshwater content of the Tables Figures Arctic agrees well with observational estimates. (4) The distribution and volume of the sea ice is shown to be improved in the latest hindcast thanks to modifications to the J I 20 drag coefficients and to some degree as well to the ice thickness distribution available in CICE. (5) On the other hand, the model overestimates the ice drift and ice thickness J I in the Beaufort Gyre. Back Close Full Screen / Esc 1 Introduction Printer-friendly Version The CONCEPTS (Canadian Operational Network of Coupled Environmental Predic- Interactive Discussion 25 Tion Systems) initiative has fostered collaborations between different federal depart- ments (Fisheries and Oceans Canada, Environment Canada and the Department of 2 Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | National Defence) that yielded the development of several operational prediction sys- tems. These include a coupled (atmosphere–ice–ocean) Gulf of Saint-Lawrence sys- GMDD tem (officially operational since June 2011, Smith et al., 2012), the Global Ice–Ocean 8, 1–52, 2015 Prediction System (GIOPS, run in real-time since March 2014, Smith et al., 2014b), 5 a Great Lakes coupled system (still in development, Dupont et al., 2012), a regional ice-only prediction system (run in real-time since July 2013, Lemieux et al., 2014) and Arctic and N-Atlantic a regional Arctic-North Atlantic ice–ocean system based on the CREG12 (Canadian high-resolution REGional) configuration with a nominal horizontal resolution of 1=12◦. The latter is the ocean and sea-ice focus of this paper. The GIOPS, Great Lakes and CREG12-based systems are based model 10 on NEMO (Nucleus for European Modelling of the Ocean, http://www.nemo-ocean.eu), while the coupled Gulf of Saint-Lawrence system is transitioning to NEMO for the ice– F. Dupont et al. ocean component. The development of these systems has benefited greatly from a col- laboration with Mercator-Océan in France. Title Page The goal of the regional system based on CREG12 is to provide Canada with short- 15 term ice–ocean predictions and analyses covering parts of the North Atlantic and whole Abstract Introduction Arctic oceans at high resolution. For this purpose, the regional system will eventually Conclusions References be coupled to the regional weather prediction system and wave prediction system of Environment Canada. The coupled system is expected to improve regional weather Tables Figures and marine forecasting services such as issuing bulletins and warnings in ice infested 20 waters for navigation, energy-exploration and northern communities requirements. As J I such, the system development has benefited from financial support from the Canadian METAREA program and the Beaufort Regional Environmental Assessment (BREA) J I 1 project. However, before the full system (analysis + forecast) can be approved for op- Back Close erational use, we need to understand how to use the forecasting component to its full Full Screen / Esc 25 potential, following the best practices of the community running at comparable resolu- tions. Hence, a series of incremental hindcasts was performed using the forecasting Printer-friendly Version component, each implementing and testing a different aspect of ocean–ice modelling. Interactive Discussion 1The analysis covers the data-assimilation aspect of any prediction system. 3 Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | These hindcasts are not long enough to test the full robustness of the model in pre- serving observed water and ice properties at climatic scales (i.e. several decades), as GMDD the initial conditions still imprint the model state after 8 years. Nevertheless, discrep- 8, 1–52, 2015 ancies between atmospheric forcing products and differences in upper-ocean and ice 5 physics are sufficient to create diverging upper-ocean and ice states and variabilities in this short period, that are worth investigating. Moreover, recent satellite missions and Arctic and N-Atlantic extensive and automotized observing in-situ programs (ARGO floats and ice-tethered high-resolution profilers to cite a few) create a wealth of data covering the hindcast period, which we ocean and sea-ice take advantage of in our validation approach. We are therefore testing the mean state model 10 of the model using a few variables, sometimes focusing on some integrated indices over time, or more extensively mapping the model-observation discrepancy in space F. Dupont et al. and time. In this contribution, we describe the model components and the validation strategy, Title Page along with results of the validation of the latest hindcast. The objective is to present to 15 the community the progress made and challenges met in developing a high resolution Abstract Introduction modelling system for the Arctic-Atlantic oceans, in the spirit of Megann et al.(2014). In Conclusions References assessing the performance of the latest hindcast in terms of ice properties (concentra- tion, thickness and velocity), we include comparison with an intermediate hindcast and Tables Figures the 1=12◦ resolution equivalent global simulation ORCA12-T321 of Mercator-Océan. 20 More precisely, Sect. 2 is divided into the description of the model (domain, model J I components and parameters; Sect. 2.1), the input bathymetry and other initial and boundary conditions (Sect. 2.2), and the description of the validation package (Sect. 2.3). J I Section 3 provides details of the hindcast simulations (Sect. 3.1), then describes the Back Close simulation results in terms of the statistics of the sea surface height, the hydrography Full Screen / Esc 25 and the general circulation (Sect. 3.2) and in terms of sea-ice metrics (concentration, thickness, volume and drift; Sect. 3.3). Section 4 concludes. Printer-friendly Version Interactive Discussion 4 Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | 2 Model setup, input data and validation package GMDD 2.1 Model description 8, 1–52, 2015 2.1.1 Domain configuration Arctic and N-Atlantic The global ORCA12 domain (ORCA family grid at a nominal horizontal resolution of ◦ high-resolution 5 1=12 in both longitudinal and latitudinal directions, Drakkar Group, 2007) is used to ocean and sea-ice derive a seamless (i.e., the “north-fold” discontinuity of the global grid is removed) re- model gional domain covering the whole Arctic Ocean and parts of the North Atlantic down ◦ to 27 N. The horizontal grid consists of 1580 × 1817 points on which resolution varies F. Dupont et al. from 8 km at the open boundary in the Atlantic Ocean to an average of 5 km in the Arc- 10 tic, and down to slightly below 2 km in some of the southern channels of the Canadian Arctic Archipelago (Fig.1). Title Page The spatial variation of the first Rossby radius of deformation is shown in Fig.2a. From about 40 km along the southern Atlantic boundary down to a few kilometers in Abstract Introduction the Labrador Sea, the Greenland, Iceland and Norwegian (GIN) seas and continental Conclusions References 15 shelves, the radius starts re-increasing in the deep Arctic Ocean to above 10 km.
Load more

Recommended publications
  • A Synthesisof Exchanges
    T H E C H A N GIN G A R CTI C OC EAN | SPE C I A L ISS U E ON T H E INT ERN AT I ONA L POLAR YEAR 20072009 A Synthesis of Exchanges $rough the Main Oceanic Gateways to the Arctic Ocean BY AGNIESZK A BESZCZYNSK A M Ö L L E R , R E B ECC A A . W O O D G AT E , C R A I G L E E , H U M FREY MELLING, A N D M I C HAE L KARCH ER Deployment of a deep mooring with an Aanderaa current meter in Fram Strait during R/V Polarstern cruise ARKXIII in 2008. Photo courtesy of A. Beszczynska-Möller 82 Oceanography | Vol.24, No.3 ABSTRACT. In recent decades, the Arctic Ocean has changed dramatically. mass, liquid freshwater, and heat through Exchanges through the main oceanic gateways indicate two main processes of global the main Arctic gateways and the esti- A Synthesis of Exchanges climatic importance—poleward oceanic heat "ux into the Arctic Ocean and export mates derived from these observations. of freshwater toward the North Atlantic. Since the 1990s, in particular during the Year-round moorings, almost uninter- $rough the Main Oceanic Gateways International Polar Year (2007–2009), extensive observational e%orts were undertaken rupted since 1990, measure Paci!c to monitor volume, heat, and freshwater "uxes between the Arctic Ocean and the in"ow through Bering Strait. Since subpolar seas on scales from daily to multiyear. &is paper reviews present-day 2004, the program has been part of the estimates of oceanic "uxes and reports on technological advances and existing US National Oceanic and Atmospheric to the Arctic Ocean challenges in measuring exchanges through the main oceanic gateways to the Arctic.
    [Show full text]
  • Module 4 Physical Oceanography
    UNIVERSITY OF THE ARCTIC Module 4 Physical Oceanography Developed by Alec E. Aitken, Associate Professor, Department of Geography, University of Saskatchewan Key Terms and Concepts • water mass • thermocline • halocline • thermohaline circulation • first-year sea ice • multi-year sea ice • sensible heat polynyas • latent heat polynyas Learning Objectives/Outcomes This module should help you to 1. develop an understanding of the physiography of the Arctic Ocean basin and its marginal seas. 2. develop an understanding of the physical processes that influence the temperature and salinity of water masses formed in the Arctic Ocean basin and its marginal seas. 3. develop an understanding of the influence of atmospheric circulation on oceanic circulation and the interaction of water masses within polar seas. 4. develop an understanding of the physical processes that contribute to the growth and decay of sea ice and the formation of polynyas. 5. provide concise definitions for the key words. Bachelor of Circumpolar Studies 311 1 UNIVERSITY OF THE ARCTIC Reading Assignments Barry (1993), chapter 2: “Canada’s Cold Seas,” in Canada’s Cold Environments, 29–61. Coachman and Aagaard (1974), “Physical Oceanography of Arctic and Subarctic Seas,” in Marine Geology and Oceanography of the Arctic Seas, 1–72. Overview The Arctic Ocean is a large ocean basin connected primarily to the Atlantic Ocean. An unusual feature of this ocean basin is the presence of sea ice. Sea ice covers less than 10% of the world’s oceans and 40% of this sea ice occurs within the Arctic Ocean basin. There are several effects of this sea ice cover on the physical oceanography of the Arctic Ocean and its marginal seas (e.g., Baffin Bay, Hudson Bay, Barents Sea): • The temperature of surface water remains near the freezing point for its salinity.
    [Show full text]
  • Arctic Ocean and Hudson Bay Freshwater Exports: New Estimates from Seven Decades of Hydrographic Surveys on the Labrador Shelf
    15 OCTOBER 2020 F L O R I N D O - L Ó PEZ ET AL. 8849 Arctic Ocean and Hudson Bay Freshwater Exports: New Estimates from Seven Decades of Hydrographic Surveys on the Labrador Shelf CRISTIAN FLORINDO-LÓPEZ,SHELDON BACON, AND YEVGENY AKSENOV National Oceanography Centre, Southampton, United Kingdom LÉON CHAFIK Department of Meteorology and Bolin Centre for Climate Research, Stockholm University, Stockholm, Sweden EUGENE COLBOURNE Fisheries and Oceans Canada, Northwest Atlantic Fisheries Centre, St. John’s, Newfoundland and Labrador, Canada N. PENNY HOLLIDAY National Oceanography Centre, Southampton, United Kingdom (Manuscript received 29 January 2019, in final form 12 May 2020) ABSTRACT While reasonable knowledge of multidecadal Arctic freshwater storage variability exists, we have little knowledge of Arctic freshwater exports on similar time scales. A hydrographic time series from the Labrador Shelf, spanning seven decades at annual resolution, is here used to quantify Arctic Ocean freshwater export variability west of Greenland. Output from a high-resolution coupled ice–ocean model is used to establish the representativeness of those hydrographic sections. Clear annual to decadal variability emerges, with high freshwater transports during the 1950s and 1970s–80s, and low transports in the 1960s and from the mid-1990s to 2016, with typical amplitudes of 2 30 mSv (1 Sv 5 106 m3 s 1). The variability in both the transports and cumulative volumes correlates well both with Arctic and North Atlantic freshwater storage changes on thesametimescale.Werefertothe‘‘inshorebranch’’of the Labrador Current as the Labrador Coastal Current, because it is a dynamically and geographically distinct feature. It originates as the Hudson Bay outflow, and preserves variability from river runoff into the Hudson Bay catchment.
    [Show full text]
  • Macrobenthos Communities of Cambridge, Mcbeth and Itirbilung Fiords, Baffin Island, Northwest Territories, Canada' ALEC E
    ARCTIC VOL. 46, NO. 1 (MARCH 1993) P. 60.71 Macrobenthos Communities of Cambridge, McBeth and Itirbilung Fiords, Baffin Island, Northwest Territories, Canada' ALEC E. AITKEN* and JUDITH FOURNER3 (Received 2 January 1992; accepted in revised form 4 November 1992) ABSTRACT. Thirtyeight marine invertebrates, including molluscs, echinoderms, polychaetesand several minor taxa, havebeen added to the previously described benthic macrofauna inhabiting Cambridge, McBeth and Itirbilung fiords in northeastern Baffin Island, Northwest Territories, Canada. The fiords lie fully within the marine arctic zone and organisms exhibiting panarctic distributions constitute the majority of speciescollected from them. Macrobenthic associations recordedin the fiords are comparable, both with respectto species composition and habitat, to benthic invertebrate associationsoccurring on the Baffin Island continental shelf andin east Greenland fiords, reflecting the broad environmental tolerances of the organisms constituting the benthic associations.Deposit-feediig organisms dominatethe fiord macrobenthos, notably nuculanid bivalves, ophiuroid echinoderms and elasipod holothurians. The foraging and locomotory activities of these organisms may influence benthic communitystructure by reducing the abundance of sessile and/or tubiculous benthos. Key words: marine benthos, eastern Baffin Island, fiords, continental shelf, zoogeography, ecology RfiSUMfi. Trente-huit invedbrts marins, y compris des mollusques, des khinodermes, des polychhtes et divers taxons mineurs ont
    [Show full text]
  • Robocza Wersja Wykazu Polskich Nazw Geograficznych Świata © Copyright by Główny Geodeta Kraju 2013
    Robocza wersja wykazu polskich nazw geograficznych świata W wykazie uwzględnione zostały wyłącznie te obiekty geograficzne, dla których Komisja Standaryzacji Nazw Geograficznych poza Granicami Rzeczypospolitej Polskiej zaleca stosowanie polskich nazw (tj. egzonimów lub pseudoegzonimów). Robocza wersja wykazu zawiera zalecane polskie nazwy wg stanu na 13 lutego 2013 r. – do czasu ostatecznej publikacji lista tych nazw może ulec niewielkim zmianom. Układ wykazu bazuje na układzie zastosowanym w zeszytach „Nazewnictwa geograficznego świata”. Wykaz podzielono na części odpowiadające częściom świata (Europa, Azja, Afryka, Ameryka Północna, Ameryka Południowa, Australia i Oceania, Antarktyka, formy podmorskie). Każda z części rozpoczyna się listą zalecanych nazw oceanów oraz wielkich regionów, które swym zasięgiem przekraczają z reguły powierzchnie kilku krajów. Następnie zamieszczono nazwy według państw i terytoriów. Z kolei nazwy poszczególnych obiektów geograficznych ułożono z podziałem na kategorie obiektów. W ramach poszczególnych kategorii nazwy ułożono alfabetycznie w szyku właściwym (prostym). Hasła odnoszące się do poszczególnych obiektów geograficznych zawierają zalecaną nazwę polską, a następnie nazwę oryginalną, w języku urzędowym (endonim) – lub nazwy oryginalne, jeśli obowiązuje więcej niż jeden język urzędowy albo dany obiekt ma ustalone nazwy w kilku językach. Jeżeli podawane są polskie nazwy wariantowe (np. Mała Syrta; Zatoka Kabiska), to nazwa pierwsza w kolejności jest tą, którą Komisja uważa za właściwszą, uznając jednak pozostałe za dopuszczalne (wyjątek stanowią tu długie (oficjalne) nazwy niektórych jednostek administracyjnych). Czasem podawana jest tylko polska nazwa – oznacza to, że dany obiekt geograficzny nie jest nazywany w kraju, w którym jest położony lub nie odnaleziono poprawnej lokalnej nazwy tego obiektu. W przypadku nazw wariantowych w językach urzędowych na pierwszym miejscu podawano nazwę główną danego obiektu. Dla niektórych obiektów podano także, w nawiasie na końcu hasła, bardziej znane polskie nazwy historyczne.
    [Show full text]
  • Ocean Current
    Ocean current Ocean current is the general horizontal movement of a body of ocean water, generated by various factors, such as earth's rotation, wind, temperature, salinity, tides etc. These movements are occurring on permanent, semi- permanent or seasonal basis. Knowledge of ocean currents is essential in reducing costs of shipping, as efficient use of ocean current reduces fuel costs. Ocean currents are also important for marine lives, as well as these are required for maritime study. Ocean currents are measured in Sverdrup with the symbol Sv, where 1 Sv is equivalent to a volume flow rate of 106 cubic meters per second (0.001 km³/s, or about 264 million U.S. gallons per second). On the other hand, current direction is called set and speed is called drift. Causes of ocean current are a complex method and not yet fully understood. Many factors are involved and in most cases more than one factor is contributing to form any particular current. Among the many factors, main generating factors of ocean current are wind force and gradient force. Current caused by wind force: Wind has a tendency to drag the uppermost layer of ocean water in the direction, towards it is blowing. As well as wind piles up the ocean water in the wind blowing direction, which also causes to move the ocean. Lower layers of water also move due to friction with upper layer, though with increasing depth, the speed of the wind-induced current becomes progressively less. As soon as any motion is started, then the Coriolis force (effect of earth’s rotation) also starts working and this Coriolis force causes the water to move to the right in the northern hemisphere and to the left in the southern hemisphere.
    [Show full text]
  • The Long and Dangerous Road to the Sargasso Sea
    Downloaded from orbit.dtu.dk on: Dec 18, 2017 Empirical observations of the spawning migration of European eels: The long and dangerous road to the Sargasso Sea Righton, David; Westerberg, H.; Feunteun, E.; Okland, F.; Gargan, P.; Amilhat, E.; Metcalfe, J.; Lobon- Cervia, J.; Sjöberg, N.; Simon, J.; Acou, A.; Vedor, M.; Walker, A.; Trancart, T.; Brämick, U.; Aarestrup, Kim Published in: Science Advances Link to article, DOI: 10.1126/sciadv.1501694 Publication date: 2016 Document Version Publisher's PDF, also known as Version of record Link back to DTU Orbit Citation (APA): Righton, D., Westerberg, H., Feunteun, E., Okland, F., Gargan, P., Amilhat, E., ... Aarestrup, K. (2016). Empirical observations of the spawning migration of European eels: The long and dangerous road to the Sargasso Sea. Science Advances, 2(10), [e1501694]. DOI: 10.1126/sciadv.1501694 General rights Copyright and moral rights for the publications made accessible in the public portal are retained by the authors and/or other copyright owners and it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights. • Users may download and print one copy of any publication from the public portal for the purpose of private study or research. • You may not further distribute the material or use it for any profit-making activity or commercial gain • You may freely distribute the URL identifying the publication in the public portal If you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim.
    [Show full text]
  • Baffin Island and West Greenland Current Systems in Northern Baffin
    Progress in Oceanography xxx (2014) xxx–xxx Contents lists available at ScienceDirect Progress in Oceanography journal homepage: www.elsevier.com/locate/pocean Baffin Island and West Greenland Current Systems in northern Baffin Bay a, b c Andreas Münchow ⇑, Kelly K. Falkner , Humfrey Melling a College of Earth, Ocean, and Environment, University of Delaware, Newark, DE 19716, USA b National Science Foundation, Arlington, VA, USA c Institute of Ocean Sciences, Sidney, British Columbia, Canada article info abstract Article history: Temperature, salinity, and direct velocity observations from northern Baffin Bay are presented from a Available online xxxx summer 2003 survey. The data reveal interactions between fresh and cold Arctic waters advected southward along Baffin Island and salty and warm Atlantic waters advected northward along western Keywords: Greenland. Geostrophic currents estimated from hydrography are compared to measured ocean currents Circulation above 600 m depth. The Baffin Island Current is well constrained by the geostrophic thermal wind rela- Arctic tion, but the West Greenland Current is not. Furthermore, both currents are better described as current Geostrophy systems that contain multiple velocity cores and eddies. We describe a surface-intensified Baffin Island Baffin Bay Current seaward of the continental slope off Canada and a bottom-intensified West Greenland Current Greenland over the continental slope off Greenland. Acoustic Doppler current profiler observations suggest that 6 3 1 the West Greenland Current System advected about 3.8 ± 0.27 Sv (Sv = 10 m sÀ ) towards the north- west at this time. The most prominent features were a surface intensified coastal current advecting 0.5 Sv and a bottom intensified slope current advecting about 2.5 Sv in the same direction.
    [Show full text]
  • A Review of the Impact of Seismic Survey Noise on Narwhal and Other
    A Review of the Impact of Seismic Survey Noise on Narwhal & other Arctic Cetaceans Report prepared for Greenpeace Nordic by Marine Conservation Research Ltd. Prepared by Cucknell, A-C., Boisseau, O., Moscrop, A. May 2015 1 Contents Executive Summary ................................................................................................................................ 7 Glossary of terms relating to seismic testing ........................................................................................ 10 1. Introduction .................................................................................................................................. 12 2. Seismic testing that will be conducted in Canadian waters of Baffin Bay in 2015 ....................... 16 Summary ....................................................................................................................................... 16 2.1 General background and information .................................................................................. 16 2.2 Brief description of the seismic program .............................................................................. 17 2.3 Seismic data acquisition: ....................................................................................................... 18 2.4 Seismic and support vessel operations: ................................................................................ 19 2.5 NEB’s Environmental Assessment Report ............................................................................
    [Show full text]
  • Warming of the Polar Water Layer in Disko Bay and Potential Impact on Jakobshavn Isbrae
    DECEMBER 2013 M Y E R S A N D R I B E R GAARD 2629 Warming of the Polar Water Layer in Disko Bay and Potential Impact on Jakobshavn Isbrae PAUL G. MYERS Department of Earth and Atmospheric Sciences, University of Alberta, Edmonton, Alberta, Canada MADS H. RIBERGAARD Centre for Ocean and Ice, Danish Meteorological Institute, Copenhagen, Denmark (Manuscript received 15 March 2012, in final form 16 August 2013) ABSTRACT A number of recent studies have shown enhanced retreat of tidewater glaciers over much of southern and western Greenland. One of the fastest retreats has occurred at Jakobshavn Isbrae, with the rapid retreat linked to the arrival of relatively warm and saline Irminger water along the west coast of Greenland. Similar links to changes in ocean water masses on the coastal shelf of Greenland were also seen on the east coast. This study presents hydrographic data from Disko Bay, additionally revealing that there was also a significant warming of the cold polar water entering Disko Bay from the mid-to-late 1990s onward. This layer, which lies at a depth of ;30–200 m, warmed by 18–28C. The heat content of the polar water layer increased by a factor of 3.6 for the post-1997 period compared to the period prior to 1990. The heat content in the west Greenland Irminger water layer between the same periods increased only by a factor of 2, but contained more total heat. The authors suggest that the changes in the polar water layer are related to circulation changes in Baffin Bay.
    [Show full text]
  • Polish Geographical Names of Undersea and Antarctic Features the Names Which “Escape” the Definition of Exonym and Endonym
    UNITED NATIONS GROUP OF EXPERTS ON GEOGRAPHICAL NAMES 10th Meeting of the UNGEGN Working Group on Exonyms Tainach, Austria, 28-30 April 2010 Polish geographical names of undersea and Antarctic features The names which “escape” the definition of exonym and endonym Prepared by Maciej Zych, Commission on Standardization of Geographical Names Outside the Republic of Poland Polish geographical names of undersea and Antarctic features The names which “escape” the definition of exonym and endonym According to the definition of exonym adopted by UNGEGN in 2007 at the Ninth United Nations Conference on the Standardization of Geographical Names, it is a name used in a specific language for a geographical feature situated outside the area where that language is widely spoken, and differing in its form from the respective endonym(s) in the area where the geographical feature is situated. At the same time the definition of endonym was adopted, according to which it is a name of a geographical feature in an official or well-established language occurring in that area where the feature is situated1. So formulated definitions of exonym and endonym do not cover a whole range of geographical names and, at the same time, in many cases they introduce ambiguity when classifying a given name as an exonym or an endonym. The ambiguity in classifying certain names as exonyms or endonyms derives from the introduction to the definition of the notion of the well-established language, which can be understood in different ways. Is the well-established language a
    [Show full text]
  • Florida Current, Gulf Stream, and Labrador Current
    FLORIDA CURRENT, GULF STREAM, AND LABRADOR CURRENT P. L. Richardson, Woods Hole Oceanographic knowledge gained in their pursuit of the sperm whale Institution, Woods Hole, MA, USA along the edges of the Stream (Figure 1). By the early Copyright & 2001 Elsevier Ltd. nineteenth century the major circulation patterns at the surface were charted and relatively well known. This article is reproduced from the 1st edition of Encyclopedia of Ocean During that century, deep hydrographic and current Sciences, volume 2, pp 1054–1064, & 2001, Elsevier Ltd. meter measurements began to reveal aspects of the subsurface Gulf Stream. The first detailed series of Introduction hydrographic sections across the Stream were begun in the 1930s, which led to a much-improved de- The swiftest oceanic currents in the North Atlantic scription of its water masses and circulation. During are located near its western boundary along the World War II the development of Loran improved coasts of North and South America. The major navigation and enabled scientists to identify and western boundary currents are (1) the Gulf Stream, follow Gulf Stream meanders for the first time. which is the north-western part of the clockwise Shipboard surveys revealed how narrow, swift, and flowing subtropical gyre located between 101N convoluted the Gulf Stream was. Stimulated by these and 501N (roughly); (2) the North Brazil Current, new observations, Henry Stommel in 1948 explained the western portion of the equatorial gyre located that the western intensification of wind-driven ocean between the equator and 51N; (3) the Labrador currents was related to the meridional variation of Current, the western portion of the counter- the Coriolis parameter.
    [Show full text]