HR: 09:15h
AN: PP41A-06 INVITED     [PDF]
TI: Understanding Abrupt Climate Change During the Last Glacial Period: Recent Developments and Outstanding Issues
AU: * Battisti, D S
EM: david@atmos.washington.edu
AF: Dept. of Atmospheric Sciences University of Washington, Box 351640, Seattle, WA 98195-1640 United States
AB: I will summarize the two leading classes of hypotheses for the cause of the abrupt, near global scale climate changes observed during the last glacial period, known as the Dansgaard-Oeschger events. The first class of hypotheses invokes instabilities in the ocean thermohaline circulation (OTC) as a causal mechanism for these abrupt climate changes, and for the millennial time scale between jumps. The second class of hypotheses invokes multiple states in the coupled atmosphere/ocean system in the tropics, and features global teleconnections that affect changes (albeit passive) in the OTC. Climate models have been used to illustrate, and then probe, these two families of hypotheses. The output from these models, when confronted with the observations, suggests that the present hypotheses are far from being a complete explanation of the observed phenomenon. In this talk I will summarize the recent modeling developments that have shed light on some of these problems (e.g., how to communicate changes in the North Atlantic to the whole Northern Hemisphere), and the issues that are still outstanding (e.g., what are the major factors that determine the equatorward extent of sea ice in the N. Atlantic?)
DE: 1620 Climate dynamics (3309)
DE: 3339 Ocean/atmosphere interactions (0312, 4504)
DE: 3344 Paleoclimatology
SC: Paleoceanography and Paleoclimatology [PP]
MN: 2003 Fall Meeting