US-France Cooperative Research: Variability in Thermohaline Circulation and North Atlantic Climate

这项为期三年的美法气候变化合作奖涉及伍兹霍尔海洋研究所和法国国家科学研究中心（CNRS）气候科学与环境实验室的研究人员。美国的Jerry F. McManus和法国的Laurent Labeyrie将领导这个合作项目，模拟和分析热盐环流的变化及其对北大西洋气候的影响。海洋热盐环流在不同的时间尺度上经历了重组，这对理解过去和现在的地球气候具有重要意义。营养指标提供了水团重新配置的重要证据。动态示踪剂可以通过定量评估深水地层和出口速率的变化，为这些信息提供理想的补充。结合水团性质和倾覆速率可以直接估计海洋热盐环流的运输。为此，美国和法国的调查人员将改进一种利用两种长寿命铀系列（231 Pa和230 Th）的方法。他们将绘制大西洋大块沉积物岩心的埋藏比（231Pa/230Th）图。此外，他们将通过高分辨率时间序列评估环流变化与气候变率之间的联系。美国小组为这次合作带来了铀系列放射化学领域的专业知识。这是由法国在空间覆盖和分辨率方面的专业知识以及访问法国IMAGES核心存储库的补充。该奖项代表了美国方面向美国国家科学基金会和法国国家科学研究中心（CNRS）联合提出的建议。美国国家科学基金会将支付美国调查人员的旅费和生活费。法国国家科学研究中心将支持法国研究人员和一名研究生访问美国。该项目将促进对海洋环流对北大西洋气候变化和气候突变的原因和潜在影响的理解。

0233483McManusThis three-year award for US-France collaboration in climate change involves researchers at the Woods Hole Oceanographic Institution and the Laboratory for Climate Sciences and Environment of the French National Center for Scientific Research (CNRS). Jerry F. McManus in the US and Laurent Labeyrie in France will lead this collaborative program to model and analyze the variability in thermohaline circulation and impact on North Atlantic climate. The ocean's thermohaline circulation has undergone reorganization on various time scales, with important implications for understanding the Earth's climate in the past and present. Nutrient proxies provide important evidence of watermass reconfigurations. Dynamical tracers may provide an ideal complement to this information by allowing quantitative evaluation of changes in the rates of deepwater formation and export. Combination of watermass properties and overturning rate could yield direct estimates of the transport by the ocean's thermohaline circulation. To this end, the US and French investigators will refine a method that utilizes two long-lived uranium series, 231 Pa and 230 Th. They will construct maps of the burial ratio (231Pa/230Th) in bulk sediment cores of the Atlantic Ocean. In addition, they will evaluate the link between changes in circulation and climate variability through high-resolution time series. The US group brings to this collaboration expertise in the area of Uranium-series radiochemistry. This is complemented by French expertise in spatial coverage and resolution and access to the IMAGES cores repository in France.This award represents the US side of joint proposals to the NSF and the French National Center for Scientific Research (CNRS). NSF will cover travel funds and living expenses for the US investigators. CNRS will support the visits of the French researchers and a graduate student to the United States. The project will advance understanding of the causes and potential impact of ocean circulation on climate change and abrupt climate change in the North Atlantic.