Doctoral Dissertation Research in Geography and Regional Science

封闭盆地中的古湖泊是过去的敏感指标 气候变化 2000年至2005年期间 一个特定湖泊的水位可以提供 局部气候，而全流域的变化揭示了过去的变化 在大气的大规模循环中。 一个假设 湖泊研究表明， 急流和相关的地面天气系统，由 大陆冰盖的衰减，影响了高海拔的时间， 晚更新世封闭盆地湖泊群。 这 该项目将在一个关键时期开发湖泊级年表， 三个盆地晚第四纪的时间间隔 俄勒冈州东部。 这些年表将用于测试 关于大气环流控制的假设 区域气候变化 时间顺序将根据 从海岸沉积物中采集的样品的放射性碳年代测定。 基于物理的蒸发模型和水量平衡模型 将被用来估计气候条件的范围 与特定的湖面高度一致 由此引起的气候 情景将被用于测试假设，高 湖泊的立场是由平均季节位置的 美国西部上空的急流。 这一研究将有助于区域地貌学的发展 一个需要进一步研究的地区，它将进一步促进我们的 了解控制区域气候的机制 变化，从而影响水文系统的响应。

Paleolakes in closed basins are sensitive indicators of past climatic variations. The chronology of the fluctuations in the level of a particular lake can provide evidence of changes in local climate, while basin-wide variations reveals past changes in the large-scale circulation of the atmosphere. One hypothesis resulting from lake studies states that latitudinal shifts in the jet stream and associated surface weather systems, resulting from decay of the continental ice sheet, affected the timing of high stands of closed basin lakes during the late Pleistocene. This project will develop lake-level chronologies during a critical interval of the late Quaternary period for three basins in eastern Oregon. These chronologies will be used to test hypotheses concerning atmospheric circulation controls of regional climatic change. Chronologies will be determined from radiocarbon dates on samples collected from shoreline sediments. A physically based evaporation model and a water balance model will be used to estimate the range of climatic conditions consistent with a specific lake level. The resulting climate scenarios will be employed in a test of the hypothesis that high lake stands were governed by the mean seasonal positions of the jet stream over the western United States. This research will contribute to the regional geomorphology of a region in need of additional study, and it will further our understanding of the mechanisms that control regional climate changes, and thus the responses of hydrological systems.