Climate History from the Paleosalinity of Lakes in the Northern Great Plains

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Predictions of future climate require reliable General Circulation Models. And the least reliable parameter estimated by current GCMs is net moisture, precipitation less evaporation. This proposal requests support to address this problem by developing new methods to reconstruct past moisture (P-E) and to compare the results to calculated values of moisture from GCM simulations. The PIs will develop a quantitative method for reconstructing past effective moisture (P-E) using diatom assemblages and ostracod geochemistry variations in 6-8 lakes which span the moisture gradients of the Great Plains. Detailed salinity fluctuations will be calibrated to the local meteorological records for the region to derive a unique transfer function. Then the transfer function will be used to reconstruct the history of salinity in the Great Plains since the last glaciation. This research is important because it will provide more accurate estimates of past precipitation and evaporation in this climatically sensitive region, and it will provide the best baseline data to compare to GCM simulations of past climate.