HR: 0830h
AN: C31C-0409    [PDF]
TI: Sea Ice Drift and Transports in the South Pacific: Model Results and Observations
AU: * Assmann, K M
EM: kassmann@awi-bremerhaven.de
AF: Alfred Wegener Institute for Polar and Marine Research, P.O.Box 120161, Bremerhaven, 27515 Germany
AU: Hellmer, H H
EM: hhellmer@awi-bremerhaven.de
AF: Alfred Wegener Institute for Polar and Marine Research, P.O.Box 120161, Bremerhaven, 27515 Germany
AU: Jacobs, S S
EM: sjacobs@ldeo.columbia.edu
AF: Lamont-Doherty Earth Observatory, Columbia University, Palisades, NY10964 United States
AB: The first comprehensive study of sea ice drift, transports and formation rates in the southeastern Pacific sector of the Southern Ocean on time scales ranging from daily to interannual variability is presented. Sea ice drift in the Amundsen Sea and its forcing and variability is analysed using data from three buoys deployed on the ice in March 2000 and results of the coupled ice-ocean model BRIOS (Bremerhaven Ice Ocean Simulations). Three drift regimes are identified with wind as the main driving force and weak oceanic influence. A first sea ice budget is presented for the Amundsen Sea with meridional and zonal transports of almost equal magnitude and weak import from the Bellingshausen Sea. Transport magnitude and variability at the western boundary towards the Ross Sea depend strongly on the interplay between zonal easterlies and westerlies and meridional winds, which leads to accumulation of sea ice in or export from the southern Amundsen Sea. The latter strongly affects sea ice conditions in the eastern Ross Sea, while western Ross Sea ice is formed locally. An enhanced northward export of from the western part of the Ross Sea induces a large import of Amundsen Sea ice into its eastern part, because the export allows the Amundsen Sea ice to move further westward. The existence of two independent sea ice regimes in the Ross Sea with exceptionally high formation rates in the western part correlates positively with a zonal salinity gradient in the water column along the Ross Ice Shelf edge and possibly reduces the need for subsurface upwelling onto the western continental shelf.
DE: 4207 Arctic and Antarctic oceanography
DE: 4215 Climate and interannual variability (3309)
DE: 4255 Numerical modeling
DE: 4540 Ice mechanics and air/sea/ice exchange processes
SC: Cryosphere [C]
MN: 2003 Fall Meeting