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

太平洋千年尺度气候变化的起源和半球联系

• 批准号: 0319016
• 负责人: Alan Mix
• 金额: $ 69.98万
• 依托单位: Oregon State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-07-01 至 2006-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0319016&HistoricalAwards=false
• 关键词: Origin; Hemispheric; Linkage; Millennial; Scale

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.

该奖项将评估各种机制，这些机制被认为是造成过去~65,000年来太平洋东部边缘高沉降率岩心中表层和浅层地下水质量千年尺度变化的原因。在东北太平洋、赤道太平洋和东南太平洋选择了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可能影响从大气-海洋耦合模式研究中得出的气候变率模式的三个假设。第一种假设认为海面温度异常通过大气从北大西洋迅速传播到北太平洋。这意味着北太平洋将作出强烈反应，而南太平洋则很少或没有反应。第二种假设认为，全球温度异常随着温盐环流的变化而缓慢传播，并预测了东南太平洋中层水温和通风的巨大变化，这些变化相对于北半球的变化是相移的。第三种假设认为，快速气候振荡起源于热带太平洋，是通过厄尔尼诺-南方涛动（ENSO）型机制产生的，并对海洋和大气产生伴随效应。这意味着热带太平洋东部海表温度和斜斜结构的重大变化，以及能量沿东缘向两极输送到两个半球。研究人员期望，基于对采样地点的仔细选择和高分辨率古气候代用物的应用，建立东太平洋千年尺度变化的空间“指纹”。这很重要，因为它将有助于解决导致该地区千年尺度变化的主要机制，特别是半球之间的联系以及热带和温带气候变率之间的相互作用。