Origin and Hemispheric Linkage of Millennial-Scale Climate Variability in the Pacific

该奖项将评估各种机制，这些机制被认为是太平洋东缘过去65，000年来高沉积速率岩心中表面和浅层地下水团千年尺度变化的原因。 选择东北太平洋、赤道太平洋和东南太平洋这三个关键区域进行详细研究，因为它们提供了一个机会来检验三个可能影响海气耦合模式研究得出的气候变率模式的假设：第一个假设假定海表温度异常通过大气从北大西洋迅速传递到北太平洋。 第二种假设认为全球温度异常对温盐环流的变化响应缓慢，并预测东南太平洋中层水温和通气量的变化较大，且相对于北方的变化发生了相位偏移;第三种假设认为快速气候振荡起源于北半球，热带太平洋通过厄尔尼诺-南方涛动（ENSO）类型的机制，伴随着对海洋和大气的影响。 这意味着热带东太平洋的海表温度（SST）和密度跃层结构发生了重大变化，能量沿东缘沿着向南北半球传输。研究人员希望，在仔细选择采样点和应用高分辨率古气候代理的基础上，建立东太平洋千年尺度变化的空间“指纹”。 这一点很重要，因为它将有助于解决造成该区域千年尺度变化的主要机制，特别是两半球之间的联系以及热带和热带外气候变异之间的相互作用。

This award will assess various mechanisms thought to be responsible for millennial-scale variability in surface and shallow subsurface water masses in high-sedimentation rate cores from the eastern margin of the Pacific over the past ~65,000 years. Three key regions were chosen for detailed study in the Northeast Pacific, Equatorial Pacific, and Southeast Pacific, because they offer an opportunity to test three hypotheses that might affect patterns of climate variability derived from coupled atmosphere-ocean model studies.The first hypothesis assumes that sea-surface temperature anomalies are transmitted rapidly from the North Atlantic to the North Pacific via the atmosphere. This implies a strong response in the North Pacific and little or no response in the south.The second hypothesis assumes that global temperature anomalies propagate slowly in response to changes in thermohaline circulation and predicts large changes in intermediate water temperatures and ventilation in the Southeast Pacific that are shifted in phase relative to changes in the northern hemisphere.The third hypothesis assumes that rapid climate oscillations originate in the tropical Pacific via El Nino-Southern Oscillation (ENSO) type mechanisms with attendant effects on the ocean and atmosphere. This implies major changes in sea-surface temperatures (SST) and pycnocline structure in the eastern tropical Pacific and transmission of energy poleward into both hemispheres along the eastern margin. The researchers expect, based on a careful selection of sampling sites and the application of high-resolution paleoclimatic proxies, to establish the spatial "fingerprint" of millennial-scale variability in the Eastern Pacific. This is important because it will help resolve the primary mechanisms responsible for millennial-scale changes in the region especially the linkage between the hemispheres and the interaction between tropical and extratropical climate variability.