Application of Transient Time Distributions to Ocean Radiocarbon Records for the Last Deglaciation

放射性碳（14C）是海洋环流的重要示踪剂。然而，虽然广泛的海洋三角洲14 C记录已经开发，这些记录的定量解释是缺乏的。由伍兹霍尔海洋研究所的研究人员领导的这项拟议中的工作将采取一种新颖的定量方法来记录最后一次冰消期的深层和表层沃茨的Delta14 C记录。该项目将生成Delta14C记录的最新汇编以及相关的不确定性估计。将对这些记录进行渡越时间分布（TTD）计算，以将深水Delta14 C浓度与地表沃茨中的浓度联系起来。具体而言，从现代水文数据中得出的TTD将用于计算表层水记录所暗示的深水Delta14C的变化，反之亦然。这种方法将测试的假设，在最后一次冰消期的深水和地表水Delta14C值的急剧下降，共同驱动的海洋通风的变化。该项目将联合海洋建模专家，物理海洋学家和古海洋学家的专业知识，以解决冰川消退条件下海洋环流的关键问题。一名研究生将参与这项研究，并将为一名本科生提供暑期支持。项目数据、计算软件和附带的“操作方法”文件将在NOAA的国家气候数据中心存档。

Radiocarbon (14C) is an important tracer of ocean circulation. However, although extensive marine Delta14C records have been developed, quantitative interpretations of these records are lacking. The proposed work, led by researchers at Woods Hole Oceanographic Institution, will take a novel, quantitative approach to Delta14C records of deep and surface waters from the last deglaciation. The project will generate an up-to-date compilation of Delta14C records with associated uncertainty estimates. Transit time distribution (TTD) calculations will be applied to these records to relate deepwater Delta14C concentrations to those in surface waters. Specifically, TTDs derived from modern hydrographic data will be used to compute the changes in deepwater Delta14C that are implied by the surface water records, and vice versa. This approach will test the hypothesis that steep declines in deep and surface water Delta14C values during the last deglaciation were jointly driven by a change in ocean ventilation. This project will unite the expertise of an ocean modeler, a physical oceanographer, and a paleoceanographer to address a key question about ocean circulation during conditions of deglaciation. A graduate student will be involved in the research, and summer support for an undergraduate student will be provided. Project data, computational software, and accompanying "how-to" documentation will be archived at NOAA's National Climatic Data Center.