HR: 08:15h
AN: OS41C-02 INVITED    [Abstracts]
TI: Circulation and water mass transformations in the Eurasian Basin and on the adjacent shelves
AU: * Rudels, B
EM: rudels@fimr.fi
AF: Finnish Institute of Marine Research, Erik Palmenin aukio 1 P.O. Box 2, Helsinki, FI-00561, Finland
AU: Schauer, U
EM: uschauer@awi-bremerhaven.de
AF: Alfred Wegener Institute, Bussestrasse 24, Bremerhaven, D-27570, Germany
AB: The Eurasian Basin, through its connections with the Nordic Seas via Fram Strait and the Barents Sea, is the most ventilated of the Arctic Ocean basins but also the part of the Arctic Ocean where the most profound transformations in water mass properties occur. In recent decades large variations in water mass characteristics have been observed. Due to the strong stratification these changes have largely been caused by variations in properties of the waters advected to the Nordic Seas and the Arctic Ocean from the south, driven by the atmospheric forcing of the large-scale circulation beyond the Arctic. The fact that temperature and salinity anomalies, advected into the Arctic Ocean through Fram Strait, now can be identified in the different basins and traced through different circulation loops suggests that the strength of the water mass transformation processes in the Arctic Ocean has weakened, the cause being mainly higher atmospheric temperature, implying less cooling, and to a smaller degree a larger atmospheric freshwater transport to the Arctic. This reduces the dense water production on the shelves and thus the ventilation of the deeper layers of the Arctic Ocean. This could signal a larger change, where the deep water formation areas in the Arctic Mediterranean Sea eventually cease to operate, and the circulation shifts from one strongly affected by thermohaline processes to one dominated by the wind field, being only modified by the thermodynamics. The Atlantic water crossing the Greenland-Scotland Ridge would then, driven by the prevailing winds, circulate around the Arctic Mediterranean Seas, tracing the loops in the different basins, and gradually becoming dense enough to supply the Greenland-Scotland overflow and the North Atlantic deep water, while the water in the deep basins would become stagnant. Observations, especially from the last 10-15 years, are used to examine the variations in the water mass characteristics, mainly in the Eurasian Basin, to determine if such changes in the water mass transformations have taken place, and if a shift between circulation modes is possible.
DE: 4207 Arctic and Antarctic oceanography (9310, 9315)
DE: 4283 Water masses
DE: 4532 General circulation (1218, 1222)
DE: 4536 Hydrography and tracers
SC: Ocean Sciences [OS]
MN: 2007 Fall Meeting