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

摘要末次冰期以剧烈的气候振荡为特征，这些振荡似乎与海洋经向翻转环流（MOC）的变化有关。MOC速率变化的直接证据仍然有限，因为传统的示踪剂只能提供过去水团结构的快照，而不能提供财产运输的信息。在本项目中，将使用一种新的水循环动力学示踪剂Pa/Th，在海洋同位素阶段3中生成大西洋MOC的6万年高分辨率连续记录。这项研究将在北大西洋亚热带和亚极地的两个高质量岩心上进行，并将与互补的沉积学和地球化学分析以及模型研究同时进行。这些数据将探索海洋-气候系统内的联系和分阶段，并为解释Pa/Th作为环流代理提供理论约束。该项目将让学生参与MIT/WHOI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来进行宣传。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.