Abstracts
SEARCH Open Science Meeting
October 27, 2003
Seattle, Washington, USA
Arctic Ocean and Sea Ice Changes, Greenhouse Forcing and the Arctic Oscillation
John W. Weatherly1
1Cold Regions Research and Engineering Lab, 72 Lyme Rd, Hanover, NH, 03755, USA, Phone 603-646-4741, Fax 603-646-4644, weather@crrel.usace.army.mil
Recent changes observed in the Arctic Ocean and sea ice are coincident with the decreasing trend in Arctic pressures and the positive phase of the Arctic Oscillation. These changes are also consistent with the climatic warming in response to increasing greenhouse gases. The pattern of sea ice drift has shown a shrinking of the anticyclonic Beaufort Gyre and greater cyclonic circulation in the Eurasian Basin after 1988. Warmer subsurface ocean temperatures in the Amundsen and Markhov Basins observed in the early 1990’s indicate a greater extent of Atlantic-layer water and a retreat of the cold halocline.
The speculated cause of this Atlantic-layer warming is the increased inflow via the Barents Sea and Fram Strait, driven by stronger and warmer northward wind forcing in the Greenland-Iceland-Norwegian (GIN) Seas. Experiments with an Arctic ice and ocean model suggest that the atmospheric circulation patterns since 1988 have driven the increasing influx of warmer, saltier Atlantic water into the Arctic. Climate simulations with a global atmosphere-ice-ocean climate model that include both the forcing from increasing greenhouse gases and natural forcing are used to investigate the response of the Arctic sea ice and ocean to present-day global climate changes. The response of the ice and ocean to the Arctic Oscillation simulation from the climate model is compared to that produced by the greenhouse forcing. The contribution of the changes in ice and ocean waters from both the AO and from greenhouse forcing can be determined independently from these climate simulations.
Abstract Categories: Drivers and Causes
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