Recent Change of the Arctic Freshwater Cycle

In terms of recent oceanographic observations, critical changes of the freshwater hydrologic cycle in the Arctic Ocean and on land may relate closely to the Arctic Oscillation. For instance, surface salinity decreased 2%o during 1987-1997 in the Beaufort Sea, and the cold halocline layer retreated in the Eurasian Basin during the 1990s. The shift of Siberian runoff to the east may be responsible for the freshening of the upper layers of the Beaufort Sea and the thinning of the cold halocline layer. In addition, the sea level rise in the Russian marginal seas is consistent with a more cyclonic ocean circulation, resulting in the increased amount of fresh water flowing out through Fram Strait. This could increase stratification in the Greenland Sea and contribute to the weakened deep convection observed there in recent years. The reduced thermohaline circulation may also impose a negative feedback by causing less northward heat flux of the Atlantic Ocean into the Nordic seas and thereby cooling northern Europe, with serious consequences for human society and terrestrial ecosystems on this planet.

Kyung-Hoon Shin

See also Arctic Ocean; Cold Halocline; Permafrost Hydrology; Salinity Anomalies; Sea Ice; Thermohaline Circulation

Further Reading

Aagaard, K. & E.C. Carmack, "The role of sea ice and other fresh water in the Arctic circulation." Journal of Geophysical Research, 94 (1989): 14485-14498 Lewis, E.L., E.P. Jones, P. Lemke, T.D. Prowse & P. Wadhams (editors), The Freshwater Budget of the Arctic Ocean, Dordrecht and Boston: Kluwer, 2000

Macdonald, R.W., D.W. Paton & E.C. Carmack, "The freshwater budget and under-ice spreading of Mackenzie River water in the Canadian Beaufort Sea based on salinity and 18O/16O measurements in water and ice." Journal of Geophysical Research, 100 (1995): 895-919 Schlosser, P. D. Bauch, R. Fairbanks & Cerhard Bnisch, "Arctic river-runoff: mean residence time on the shelves and in halo-cline." Deep Sea Research, 41 (1994): 1053-1068 Study of Environmental Arctic Change (SEARCH), Science Plan, edited by J. Morison, V. Alexander, L. Codispoti, T. Delworth, B. Dickson, H. Eicken, J. Grebmeier, J. Kruse, J. Overland, J. Overpeck, P. Schlosser, M. Serreze & J. Walsh, Seattle: Polar Science Center, Applied Physics Laboratory, University of Washington, 2001 Vörösmarty, C.J., L.D. Hinzman, B.J. Peterson, D.H. Bromwich, L.C. Hamilton, J. Morison, V.E. Romanovsky, M. Sturm & R.S. Webb, The Hydrologic Cycle and its Role in Arctic and Global Environmental Change: A Rationale and Strategy for Synthesis Study, Fairbanks, Alaska: Arctic Research Consortium of USA, 2001 UNESCO (United Nations Educational, Scientific, and Cultural Organization), World Water Balance and Water Resources of the Earth, Study and Report in Hydrology, 25, Paris, 1978

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