Kalman Filtering and Smoothing of Sediment Records from the Atlantic Ocean over the last 20 KYRS

古气候学是一个快速发展的领域，其记录的持续性提高了精确度和年代学。随着这类记录的数量增加，如何在存在动力学模型的情况下解释它们的问题已经出现。这项工作由马萨诸塞州伍兹霍尔海洋研究所的一名研究人员领导，开发了一种逆方法，将海表面温度和其他海洋特性的长时间序列同化到海洋环流的三维模型中，这些特性是通过分析沉积物岩心产生的。数据同化在地质时间尺度上构成的计算挑战将通过依赖简化动力学的模型和分区卡尔曼滤波和平滑器来解决。滤光器将用于驱动模型，收集北大西洋过去2万年的沉积物记录。将以与沉积物数据和海洋动力学相一致的方式估计这一时间间隔内大尺度水文锋面的移动和随之而来的环流变化，从而能够检验各种古海洋学假说。通过估计过去20,000年来北大西洋随时间变化的状态，该项目将提供一个视角，了解根据仪器记录推测的海洋环流的持续变化。该项目汇集了一名海洋模型师、一名古海洋学家和两名物理海洋学家，以确保对该项目的各个方面采取强有力的方法。这些参与者包括来自法国机构的两名合作者。资金支持伍兹霍尔海洋研究所的一名研究生和一名博士后学者。

Paleoclimatology is a rapidly evolving field, with a sustained production of records with improved accuracy and chronology. As the number of such records increases, the question of how to interpret them in the presence of a dynamical model has emerged. This work, led by a researcher at the Woods Hole Oceanographic Institution in Massachusetts, develops an inverse method for assimilating long time series of sea surface temperature and other oceanic properties, such as those generated from the analysis of sediment cores, into three-dimensional models of ocean circulation. The computational challenge posed by data assimilation over geologic time scales will be addressed by relying on a model with simplified dynamics and on a partitioned Kalman filter & smoother. The filter & smoother will be applied to drive the model with a collection of sediment records over the last 20,000 years from the North Atlantic Ocean. The movements of large-scale hydrographic fronts and the attendant circulation changes over this time interval will be estimated in a manner that is consistent with both sediment data and ocean dynamics, thereby allowing various paleoceanographic hypotheses to be tested. By estimating the time-dependent state of the North Atlantic Ocean over the last 20,000 years, the project will provide a perspective on ongoing changes in ocean circulation that are postulated from instrumental records. This project brings together an ocean modeler, a paleoceanographer, and two physical oceanographers to ensure a robust approach to the various aspects of the project. These participants include two collaborators from French institutions. Funding supports a graduate student and a post-doctoral scholar at the Woods Hole Oceanographic Institution.