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Large-scale Temperature and Salinity Changes in the Upper Canadian Basin of the Arctic Ocean at a Time of a Drastic Arctic Oscillation Inversion : Volume 9, Issue 3 (10/05/2012)

By Bourgain, P.

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Book Id: WPLBN0003986875
Format Type: PDF Article :
File Size: Pages 38
Reproduction Date: 2015

Title: Large-scale Temperature and Salinity Changes in the Upper Canadian Basin of the Arctic Ocean at a Time of a Drastic Arctic Oscillation Inversion : Volume 9, Issue 3 (10/05/2012)  
Author: Bourgain, P.
Volume: Vol. 9, Issue 3
Language: English
Subject: Science, Ocean, Science
Collections: Periodicals: Journal and Magazine Collection (Contemporary), Copernicus GmbH
Historic
Publication Date:
2012
Publisher: Copernicus Gmbh, Göttingen, Germany
Member Page: Copernicus Publications

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Zhao, J., Shi, J., Gascard, J. C., & Bourgain, P. (2012). Large-scale Temperature and Salinity Changes in the Upper Canadian Basin of the Arctic Ocean at a Time of a Drastic Arctic Oscillation Inversion : Volume 9, Issue 3 (10/05/2012). Retrieved from http://www.worldlibrary.net/


Description
Description: LOCEAN, Université Pierre et Marie Curie, Paris, France. Between 2008 and 2010, the Arctic Oscillation index over Arctic regions shifted from positive values corresponding to more cyclonic conditions prevailing during IPY period (2007–2008) to extremely negative values corresponding to strong anticyclonic conditions in 2010. In this context, we investigated the recent large scale evolution of the upper Western Arctic Ocean based on temperature and salinity summertime observations collected during icebreaker campaigns and from Ice-Tethered Platforms (ITP) drifting across the region in 2008 and 2010. Particularly, we focused on (1) the freshwater content which was extensively studied during previous years, (2) the Near Surface Temperature Maximum due to incoming solar radiation and (3) the water masses advected from the Pacific and Atlantic Oceans into the deep Arctic Ocean.

The observations revealed a freshwater content change in the Canadian basin during this time period. South of 80° N, the freshwater content increased, while north of 80° N, less freshening occurred in 2010 compared to 2008. This was more likely due to the strong anticyclonicity characteristic of a low AO index mode that enhanced both a wind-generated Ekman pumping in the Beaufort Gyre and a diversion of the Siberian rivers runoff toward the Eurasian basin at the same time.

The Near Surface Temperature Maximum due to incoming solar radiation was almost 1 °C colder in the Southern Canada basin (south of 75° N) in 2010 compared to 2008 which contrasted with the positive trend observed during previous years. This was more likely due to higher summer sea ice concentration in 2010 compared to 2008 in that region, and surface albedo feedback reflecting more sun radiation back in space.

The Pacific waters were also subjected to strong spatial and temporal variability between 2008 and 2010. In the Canada basin, both Summer and Winter Pacific waters influence increased between 75° N and 80° N. This was more likely due to a strong recirculation within the Beaufort Gyre. In contrast, south of 75° N, the PaW influence decreased indicative of the fact that they were not responsible for the freshening already mentioned, due to other sources. In addition, in the vicinity of the Chukchi Sea, both Summer and Winter Pacific waters were significantly warmer in 2010 than in 2008 as a consequence of a general warming trend of the Pacific waters entering in the deep Arctic Ocean since 2008.

Finally, the warm Atlantic water remained relatively stable between 2008 and 2010 in the Canadian basin despite strong atmospheric shift, probably because of large time lag response. Atlantic water variability resulting from the presence of a warm pulse-like event in this region since 2005 was still noticeable even if a cooling effect was observed at a rate of 0.015 °C yr−1 between 2008 and 2010 in that region.


Summary
Large-scale temperature and salinity changes in the upper Canadian basin of the Arctic Ocean at a time of a drastic Arctic Oscillation inversion

Excerpt
Aagaard, K. and Carmack, E. C.: The role of sea ice and other fresh water in the arctic circulation, J. Geophys. Res., 94(10), 14485–14498, 1989.; Aagaard, K., Coachman, L. K., and Carmack, E.: On the halocline of the Arctic Ocean, Deep-Sea Res. Pt. A, 28, 529–545, 1981.; Bourgain, P. and Gascard, J. C.: The Arctic Ocean halocline and its interannual variability from 1997 to 2008, Deep-Sea Res. Pt. I, 58, 745–756, 2011.; Beal, M. A., Edvalson, F., Hunkins, K., Molloyl, A., and Ostenso, N.: The floor of the Arctic Ocean: Geographic names, ARCTIC: Journal of the Arctic Institute of North America, The Arctic Institute of North America, 19(3), 213–284, 1966.; Bourgain, P. and Gascard, J.C: The Atlantic and Summer Pacific waters variability in the Arctic Ocean from 1997 to 2008, Geophys. Res. Lett., 39, L05603, doi:10.1029/2012GL051045, 6 pp., 2012.; Carmack, E., Macdonald, R., Perkin, R., McLaughlin, F., and Pearson, R.: Evidence for Warming of Atlantic Water in the Southern Canadian Basin of the Arctic Ocean: evidence from the Larsen-93 Expedition, Geophys. Res. Lett., 22, 1061–1065, 1995.; Coachman, L. K. and Barnes, C. A.: The Contribution of Bering Sea Water to the Arctic Ocean, Number 249 from the Department of Oceanography, University of Washington, 1961.; Condron, A., Winsor, P., Hill, C., and Menemenlis, D.: Simulated response of the arctic freshwater budget to extreme NAO wind forcing, J. Climate, 22, 2422–2437, doi::10.1175/2008JCLI2626.1, 2009.; Coupel, P., Jin, H. Y., Ruiz-Pino, D., Chen, J. F., Lee, S. H., Li, H. L., Rafizadeh, M., Garçon, V., and Gascard, J. C.: Phytoplankton distribution in the Western Arctic Ocean during a summer of exceptional ice retreat, Biogeosciences Discuss., 8, 6919-6970, doi:10.5194/bgd-8-6919-2011, 2011.; Dickson, R. R., Meincke, Malmberg, S. A., and Lee, A. J.: The Great Salinity Anomaly in the northen North Atlantic 1968–1982, Prog. Oceanogr., 20, 103–151, 1988.; Dickson, R. R., Osborne, T. J., Hurrell, J. W., Meincke, J., Blindheim, J., Adlandsvik, B., Vinje, T., Alekseev, G., and Maslowski, W.: The Arctic Ocean response to the North Atlantic oscillation, J. Climate, 13, 2671–2696, 2000.; Ekwurzel, B., Schlosser, P., Mortlock, R. A., and Fairbanks, R. G.: River runoff, sea ice meltwater, and Pacific water distribution and mean residence times in the Arctic Ocean, J. Geophys. Res., 106(C5), 9075–9092, 2001.; Gerdes, R., Karcher, M., Köberle, C., and Fieg, K.: Simulating the long term variability of liquid freshwater export from the Arctic Ocean , Arctic-Subarctic Ocean Fluxes: Defining the role of the Northern Seas in Climate, edited by:: Dickson, B., Meincke, J., and Rhines, P., Springer, ISBN: 978-1-4020-6773-0, 2008.; Giles, K. A., Laxon, S. W., Ridout, A. L., Wingham, D. J., and Bacon, S.: Western Arctic Ocean freshwater storage increased by wind-driven spin-up of the Beaufort Gyre, Nat. Geosci., 5, 194–197; doi:10.1038/ngeo1379, 2012.; Ivanov, V. V., Polyakov, I. V., Dmitrenko, I. A., Hansen, E., Repina, I. A., Kirillov, S. A., Mauritzen, C

 

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