HR: 1340h
AN: A23B-0788    [Abstracts]
TI: Southern Ocean response to high-frequency winds
AU: * Weijer, W
EM: wweijer@ucsd.edu
AF: Scripps Institution of Oceanography, 9500 Gilman Drive, La Jolla, CA 92093 United States
AU: Gille, S T
EM: sgille@ucsd.edu
AF: Scripps Institution of Oceanography, 9500 Gilman Drive, La Jolla, CA 92093 United States
AB: The Southern Ocean displays variability on many spatial and temporal scales, the sources of which are not always clear. For example, many studies have addressed the relation between Drake Passage transport variations and wind stress variability, but the complexity of the Southern Ocean dynamics and the sparseness of data in the region make it difficult to establish a consistent picture. This study addresses the response of the Southern Ocean to high-frequency wind forcing. Results will be presented of numerical simulations with a barotropic model of the Southern Ocean, forced with a stochastic wind stress. For periods longer than roughly 5 days, the response is well described by the so-called Southern Mode. For shorter periods the response is dominated by the excitation of barotropic normal modes. A main result is that the excitation of resonant modes leads to a complicated phase relationship between the transport and the wind stress, suggesting that the classical notion of transport passively lagging forcing may be inadequate when eigenmodes come into play. Furthermore, it will be shown that form stress, rather than friction, balances the wind stress in the dynamics of the Southern Mode.
DE: 4255 Numerical modeling
DE: 4504 Air/sea interactions (0312)
DE: 4556 Sea level variations
SC: Atmospheric Sciences [A]
MN: 2004 AGU Fall Meeting