Heinrich-Scale Events in Western North America and the Northeastern Pacific? Testing Possible Mechanisms

该奖项支持一项合作研究工作，以测试有关北美西部和东北太平洋千年尺度气候波动发生的假设。来自加利福尼亚和俄勒冈州海洋沉积物的初步数据，来自太平洋西北湖泊的花粉记录，以及来自北美西部的冰川记录显示，气候事件似乎与北大西洋海因里希事件有关。本研究将验证两个假设：1)起源于北大西洋的气候事件通过温盐环流及其对海洋表面特征和大气环流的影响传递到北太平洋和北美西部；2)北大西洋、北美和东北太平洋的气候共同依赖于劳伦泰德冰盖的海拔高度及其对大气环流的影响。通过分析太平洋东北部和北美西部一系列地理地点的古气候记录，这些假设将受到限制。本研究的重点将包括：海洋上升流和近地表平流的约束、深海特性和陆地植被，并将这些数据与模式输出进行比较。将陆地和海洋的记录与严格限定的年代学联系起来，以及与海洋岩心中花粉和陆源沉积物的地层联系起来，将会取得重大进展。

9615822 Whitlock This award supports a collaborative research effort to test hypotheses regarding the occurrence of millennial-scale climate fluctuations now recognized in western North America and the northeastern Pacific Ocean. Preliminary data from marine sediments off California and Oregon, pollen records from Pacific Northwest lakes, and glacial records from western North America reveal climate events that appear to be related to the Heinrich events of the North Atlantic. This study will test two hypotheses: 1) that climate events originating in the North Atlantic are transmitted to the North Pacific Ocean and western North America via thermohaline circulation and its influence on surface ocean characteristics and circulation of the atmosphere, and 2) that climates of the North Atlantic, North America, and the northeast Pacific depend jointly on the elevation of the Laurentide Ice Sheet and its influence on atmospheric circulation. These hypotheses will be constrained by analyzing the paleoclimate record in a geographic array of sites in the northeastern Pacific Ocean and in western North America. Focus of this study will include: constraints on oceanic upwelling and near-surface advection, deep ocean properties and vegetation on land, and comparing these data with model output. A significant advance will come from linking the records from land and sea with a well- constrained chronology, and with stratigraphic links of pollen and terrigenous sediment in marine cores.