HR: 14:15h
AN: OS52L-02    [PDF]
TI: A Systematic Approach to Determine Thresholds of the Ocean's Thermohaline Circulation
AU: * Dijkstra, H A
EM: dijkstra@atmos.colostate.edu
AF: Department of Atmospheric Science, Colorado State University, Foothills Campus, Fort Collins, CO 80526 United States
AU: Weijer, W
EM: wweijer@ucsd.edu
AF: Scripps Institute of Oceanography, University of California at San Diego, 9500 Gilman Drive, La Jolla, CA 92093 United States
AB: A systematic approach is presented to determine thresholds in freshwater flux perturbations related to abrupt changes in the ocean's thermohaline circulation. The typical problem considered is the response of a thermohaline driven flow to a localized change, of specified strength and duration, in the surface freshwater flux. The initial transient response due to the freshwater anomaly is considered as a finite amplitude perturbation. An estimate of this response can be obtained by using ideas from dynamical systems theory. Central quantity to determine whether such a perturbation leads to instability (i.e., to a 'collapsed' state) is the sign of the tendency of a specific energy functional. The approach is briefly illustrated with a simple box model and then shown to give good results in a global ocean general circulation model.
DE: 1635 Oceans (4203)
DE: 3220 Nonlinear dynamics
DE: 4255 Numerical modeling
DE: 4532 General circulation
SC: Ocean Sciences [OS]
MN: 2004 Ocean Sciences Meeting