HR: 1340h
AN: PP23B-1346    [Abstracts]
TI: Climate and Ocean Circulation at the Paleocene/Eocene Boundary and Their Sensitivity to Atmospheric CO2
AU: * Heinemann, M
EM: malte.heinemann@zmaw.de
AF: Max Planck Institute for Meteorology, Bundesstrasse 53, Hamburg, 20146,
AU: Marotzke, J
EM: jochem.marotzke@zmaw.de
AF: Max Planck Institute for Meteorology, Bundesstrasse 53, Hamburg, 20146,
AB: We study the climate at the Paleocene/Eocene (PE) boundary (55 Ma) using the coupled AO-GCM ECHAM5/MPI- OM. Applying simple PE boundary conditions and a CO2 concentration of 560ppm already yields a very warm, sea-ice free climate. Still, the Pole-Equator SST gradient is higher than suggested by proxy data. The simulated ocean circulation in the Atlantic is characterized by deepwater formation in the Proto-Labrador Sea. This North Atlantic Deepwater (NADW) flows southward as a western boundary current below the depth of the open Panama Strait. For a CO2 concentration of only 280ppm, the NADW formation becomes even stronger and deeper. By contrast, Nunes and Norris (2006) inferred a northward Atlantic bottom water track for the period before the Paleocene/Eocene Thermal Maximum from d13C gradients. The Pacific Meridional Overturning Circulation for a CO2 concentration of 560ppm is quite weak. Yet for the reduced atmospheric CO2 concentration of 280ppm, strong southern deepwater formation occurs.
DE: 1605 Abrupt/rapid climate change (4901, 8408)
DE: 4928 Global climate models (1626, 3337)
DE: 4930 Greenhouse gases
DE: 4948 Paleocene/Eocene thermal maximum
DE: 4962 Thermohaline
SC: Paleoceanography and Paleoclimatology [PP]
MN: 2007 Fall Meeting