HR: 12:05h
AN: PP22A-08    [Abstracts]
TI: Model-Data Comparisons for Past Warm Climates: How Do We Know When We've Got It Right?
AU: * Bice, K L
EM: kbice@whoi.edu
AF: Department of Geology and Geophysics, Woods Hole Oceanographic Institution, Woods Hole, MA 02543, United States
AU: Heinemann, M
EM: malte.heinemann@zmaw.de
AF: Max Planck Institute for Meteorology, Bundesstrasse 53, Hamburg, D-20146, Germany
AB: In order to use paleoclimate reconstructions to evaluate the quality of climate system models, we have to assume at some point that our interpretations of climate proxy data are correct. Without that, there is no argument to be made that a model's sensitivity to some system change is right or wrong. (We also must assume that we have identified and reconstructed properly every relevant system boundary condition and forcing, but this is far from the current state of the art.) We generally can believe that the analytical precision with which we measure a sample property is adequate (isotope, metal or compound ratios, magnetism, component weight percentage, etc.). But we also have to believe that a primary environmental signal is preserved in a sample (i.e. that there has been no diagenetic alteration of the quantity or quality being measured). And, most difficult by far, we have to believe that we understand properly how to translate the measurement that is made into the value of the original environmental variable (ocean temperature, atmospheric composition, percent deciduous forest, continental position and elevation, etc.) Addressing the vital issue of climate model sensivity to atmospheric carbon dioxide concentration, we examine the results from coupled and uncoupled model sensitivity experiments in comparison to multiple proxy reconstructions of carbon dioxide and surface temperatures for past warm climate intervals during the Cretaceous and Eocene. The comparison, like all paleoclimate model-data comparisons, forces the question, "How do we know when we've got it right?"
DE: 0473 Paleoclimatology and paleoceanography (3344, 4900)
DE: 1620 Climate dynamics (0429, 3309)
DE: 1622 Earth system modeling (1225)
DE: 3337 Global climate models (1626, 4928)
DE: 4930 Greenhouse gases
SC: Paleoceanography and Paleoclimatology [PP]
MN: 2007 Fall Meeting