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

对未来气候的预测需要可靠的大气环流模式。目前GCMs估算的最不可靠的参数是净湿度、降水、蒸发量。本提案要求通过开发新的方法来重建过去的湿度（P-E），并将结果与GCM模拟的计算值进行比较，以解决这一问题。该项目将开发一种定量方法，利用硅藻组合和介形虫地球化学变化重建大平原6-8个湖泊的过去有效水分（P-E）。详细的盐度波动将根据该地区的当地气象记录进行校准，以得出一个独特的传递函数。然后利用传递函数重建末次冰期以来大平原盐度变化的历史。这项研究很重要，因为它将提供对这一气候敏感地区过去降水和蒸发的更准确估计，并将提供与GCM过去气候模拟进行比较的最佳基线数据。

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.