HR: 0800h
AN: PP31A-0888    [Abstracts]
TI: A Model Perspective on Factors Influencing the Stability Characteristics of the North Atlantic Meridional Overturning Circulation During the Last Glacial Cycle
AU: * Gulden, L E
EM: gulden@mail.utexas.edu
AF: Department of Geological Sciences, University of Texas at Austin, The University of Texas at Austin Department of Geological Sciences 1 University Station C1140, Austin, TX 78712 United States
AU: Jackson, C S
EM: charles@utig.ig.utexas.edu
AF: University of Texas - Institute for Geophysics, University of Texas Institute for Geophysics 4412 Spicewood Springs Rd., Bldg 600, Austin, TX 78759 United States
AU: Marchal, O
AF: Woods Hole Oceanographic Institution, Woods Hole Oceanographic Institution, Woods Hole, MA 02543 United States
AU: Stocker, T F
AF: Climate and Environmental Physics, Physics Institute, University of Bern, Climate and Environmental Physics University of Bern, Physics Institute Sidlerstrasse 5, Bern, 3012 Switzerland
AB: Much of the variance in Holocene and Late Pleistocene climate is attributed to changes in the stability characteristics of the North Atlantic meridional overturning circulation (MOC). Proxy records indicate that global climate was relatively stable throughout the Holocene, moderately stable during the coldest periods of the last glaciation (Stages 2 and 4), and least stable throughout Stage 3. An examination is made of how changes during the last 120 kyr in glacial-cycle forcings (waxing and waning of continental ice sheets, variations in atmospheric carbon dioxide concentration, and changes in Earth's orbital geometry) affected the stability thresholds of the MOC to freshwater forcing. These inferences will be drawn from the results of runs of the seasonally resolving Bern climate model (Schmittner and Stocker, 1999, J Clim), which is composed of a zonally averaged ocean model (Wright and Stocker, 1992, J Clim) coupled to an energy-balance model of the atmosphere that parameterizes the meridional transport of heat and moisture.
DE: 4255 Numerical modeling
DE: 1699 General or miscellaneous
DE: 1620 Climate dynamics (3309)
SC: Paleoceanography and Paleoclimatology [PP]
MN: 2004 AGU Fall Meeting