HR: 11:30h
AN: GC11A-05 INVITED     [PDF]
TI: A Minimum Thermodynamic Model for the Bipolar Seesaw
AU: * Stocker, T F
EM: stocker@climate.unibe.ch
AF: Thomas F. Stocker, Climate and Environmental Physics, Physics Institute, University of Bern, Bern, 3012 Switzerland
AU: Johnsen, S J
EM: sigfus@gfy.ku.dk
AF: Sigfus J. Johnsen, Niels Bohr Institute, University of Copenhagen, Copenhagen, 2200 Denmark
AB: The simplest possible model is proposed to explain a large fraction of the millennial climate variability measured in the isotopic composition of Antarctic ice cores. The model results from the classic bipolar seesaw by coupling it to a heat reservoir. In this "thermal bipolar seesaw" the heat reservoir convolves northern time signals with a characteristic time scale. Applying the model to the data of GRIP and Byrd we demonstrate that maximum correlation can be obtained using a time scale of about 1000-1500 years. Higher correlations are obtained by first filtering out the long-term variability which is due to astronomical and greenhouse gas forcing and not part of the thermal bipolar seesaw. The model resolves the apparent confusion whether northern and southern climate records are in or out-of-phase, synchronous, or time lagged.
DE: 1620 Climate dynamics (3309)
DE: 3344 Paleoclimatology
DE: 4267 Paleoceanography
SC: Global Climate Change [GC]
MN: 2003 Fall Meeting