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

上一个冰期的特点是剧烈的气候振荡，这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，因为传统示踪剂只能提供过去水团结构的快照，而没有关于属性运输的信息。在该项目中，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期间产生高分辨率、连续6万年的大西洋MOC记录。这项研究将在来自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拟研究并行进行。这些数据将探索海洋-气候系统内的联系和分期，并为将Pa/Th作为环流替代物的解释提供理论上的限制。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，并通过国家科学基金会资助和自愿的努力，为本科生提供学习方面的研究经验。PIS将继续通过在大学校园发表演讲以及在报纸和电台广播等媒体上进行讨论的方式进行外联。所有数据都将存档，并通过世界卫生组织和国家数据中心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.