Investigating the Role of Ocean Circulation in Climate Change During the Last Ice Age Using 231Pa/230Th

上一个冰河时代的特征是剧烈的气候振荡，这种振荡似乎与海洋纬向翻转环流（MOC）的变化有关。MOC速率变化的直接证据仍然有限，因为传统示踪剂只能提供过去水团配置的快照，而没有关于财产运输的信息。在这个项目中，将使用一种新的水循环动态示踪剂Pa/Th，在海洋同位素第三阶段制作大西洋MOC的高分辨率连续60 000年记录。这项研究将对来自亚热带和亚极地北大西洋的两个高质量岩心进行，并将与补充性沉积学和地球化学分析以及建模研究同时进行。这些数据将探讨海洋-气候系统内的联系和阶段性变化，并为把Pa/Th解释为环流代用指标提供理论上的限制。该项目将让学生参与麻省理工学院/世界卫生组织的研究和教学，并通过NSF资助和自愿努力为本科生提供研究经验。 PI将继续通过在大学校园的演讲和在报纸和广播等媒体上的讨论进行宣传。 所有数据都将存档，并通过WHOI和NGDC的网络访问向科学界和公众提供。

ABSTRACT 0602384The last ice age was characterized by dramatic climate oscillations that appear to be linked to changes in the oceans meridional overturning circulation (MOC). Direct evidence for changes in the rate of MOC remains limited because traditional tracers can only provide snapshots of past water mass configurations without information about property transport. In this project, a new dynamical tracer of water circulation, Pa/Th, will be used to produce high-resolution, continuous 60,000-year record of MOC in the Atlantic Ocean during marine isotope stage 3. This research will be conducted on two high-quality cores from the subtropical and subpolar North Atlantic Ocean and will be carried out in parallel with complementary sedimentological and geochemical analyses as well as modeling studies. These data will explore linkages and phasing within the ocean-climate system and provide theoretical constraints on the interpretation of Pa/Th as a circulation proxy. This project will involve students in their research and in teaching at MIT/WHOI, and through NSF-funded and voluntary efforts to provide undergraduates with research experience in their studies. The PIs will continue outreach through presentations at college campuses and discussions in media such as newspapers and radio broadcasts. All data will be archived and made available to the scientific community as well as to the general public through web-based access at WHOI and NGDC.