A coupled ocean-atmosphere climate model is used to provide concrete predictions of climate properties and processes in the eastern tropical Pacific during the early Paleogene in equilibrium with 560 ppm pCO2. This climate model simulation provides estimates of upwelling, temperature, current velocities, thermocline tilt, and salinity (independent of climate proxy interpretations) to provide a framework for comparison with Leg 199 data. The simulated east-west temperature gradients are comparable, although somewhat (~2°C) stronger, to modern temperature gradients, with vigorous upwelling in the eastern equatorial Pacific. Near-surface and intermediate-depth current structures are extremely variable, both spatially and temporally, making generalizations about current directions and strengths difficult. A North Atlantic water mass traveling through the open Panamanian Isthmus at intermediate to deep levels in the equatorial Pacific provides a signal of "young" water at depth at the location of Leg 199 sites. Estimates of seawater and calcium carbonate oxygen isotopic compositions are also made. Some implications of possible differences between findings based on data from Leg 199 and this modeling study are briefly discussed.
1Examples
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2Danish Center for Earth System Science, Niels Böhr Institute, Denmark. rop@dcess.ku.dk
Ms 199IR-103