Collaborative Research: "EaSM-3": The Role of Ocean Eddies in Decadal Prediction

对环境预测的需求日益增长，这种预测包括更广泛的空间和时间尺度，并包括更完整的天气和气候过程的表示。满足这一需求需要一个统一的方法，挑战天气和气候科学之间的传统界限，并需要一个更综合的方法，更高的空间分辨率模型，解决重要的动力过程及其相互作用。对可预测性的估计可能对这些模型所捕捉的过程和现象的范围很敏感。该项目旨在全面评估海洋涡旋如何影响十年期的可预测性。该项目提出的一个关键问题是，预测系统实际上是否需要初始化单个海洋涡旋，或者仅仅将海洋涡旋包括在预测系统中就足够了？探讨这个问题对年代际预测系统的设计具有深远的意义。该项目将通过对一名研究生进行重要的气候多变性和变化问题方面的教育，并对一名博士后研究员进行辅导，促进劳动力发展。将向十年预测和气候服务界提供关于海洋涡旋如何影响十年可预测性以及如何在涡旋分辨模型中对其进行初始化的建议。社区地球系统模型（CESM）和数据同化研究试验台（DART）建模框架内的高分辨率同化新能力将提供给CESM气候建模社区。更广泛地说，任何与DART集合同化系统接口的模型都可以利用将在本项目下开发的数据同化基础设施的进步和工具开发。 还将随时提供广大气候界感兴趣的海洋涡旋分辨模拟、数据同化产品、可预报性和实验预报结果，这一研究项目所依据的假设是，与海洋涡旋有关的动力和物理过程以及与大气的伴随相互作用对十年期可预报性有巨大而有力的影响。拟议的研究旨在量化这种影响，通过诊断可预测性研究分析长涡分辨模拟和预测“完美”模型的可预测性实验。将开发必要的工具和能力，以涡动分辨分辨率初始化耦合模型的海洋部分。新的涡分辨资料同化系统将通过试验预报进行评估。该项目还寻求开发一个数据同化系统，用于在海洋涡旋分辨尺度上进行十年期预测。目前的基于集合的海洋数据同化方法，在涡允许的分辨率将被应用到涡解决模式。为了支持调整新的高分辨率数据同化系统，将开发新的工具，用于估计同化中使用的分辨率相关的观测误差统计。分辨率依赖的观测误差统计的规格是数据同化的巨大重要性，和工具，以支持这一点，目前还没有。高分辨率海洋数据同化系统的局限性将从其计算成本及其在限制涡流场方面的效力方面进行评估，该项目将制定战略，以解决这些局限性，这些局限性与被确定为十年期可预测性研究一部分的十年期预测的需要相一致。最后，数据同化系统将在2006年至今的数据丰富的年份中以涡分辨尺度实施，并用实验预测进行评估。

There is a growing demand for environmental predictions that include a broader range of space and time scales and that include a more complete representation of weather and climate processes. Meeting this demand necessitates a unified approach that challenges the traditional boundaries between weather and climate science, and requires a more integrated approach with much higher spatial resolution models that resolve important dynamical processes and their interactions. Estimates of predictability are likely to be sensitive to the range of processes and phenomena captured by these models. This project seeks to provide a comprehensive assessment of how ocean eddies affect decadal predictability. One of the key questions this project asks is, do prediction systems actually need to initialize individual ocean eddies or is simply including ocean eddies in the prediction system sufficient? Answering this question has profound implications in the design of decadal prediction systems. This project will contribute to workforce development through the education of a graduate student in important climate variability and change problems, and the mentoring of a post-doctoral researcher. The decadal prediction and climate services community will be advised regarding how ocean eddies impact decadal predictability and how to initialize them in eddy resolving models. The new capacity for high-resolution assimilation within the freely accessible Community Earth System Model (CESM) and Data Assimilation Research Testbed (DART) modeling frameworks will be available to the CESM climate modeling community. More broadly, any model that interfaces with the DART ensemble assimilation system can leverage the data assimilation infrastructure advances and tool development that will be developed under this project. Ocean eddy-resolving simulations, data assimilation products, predictability and experimental prediction results that are of interest to the broader climate community will be also made readily available.This research project is based on the hypothesis that the dynamic and physical process associated with ocean eddies and the accompanying interactions with the atmosphere have a large and robust impact on decadal predictability. The proposed research seeks to quantify this effect through diagnostic predictability research by analyzing long eddy resolving simulations and prognostic "perfect" model predictability experiments. Tools and capabilities that are necessary to initialize the ocean component of coupled models at eddy resolving resolutions will be developed. The new eddy resolving data assimilation system will be evaluated through experimental prediction. The project also seeks to develop a data assimilation system appropriate for initializing decadal prediction at ocean eddy-resolving scales. The current ensemble-based ocean data assimilation method available at eddy-permitting resolution will be applied to the eddy-resolving model. To support tuning the new high-resolution data assimilation system, novel tools for estimating the resolution-dependent observational error statistics used in the assimilation will be developed. The specification of resolution-dependent observational error statistics is of enormous importance for data assimilation, and tools to support this are currently unavailable. The limitations of the high-resolution ocean data assimilation system will be assessed in terms of its computational cost and its efficacy at constraining the eddy field, and the project will develop strategies for addressing these limitations that are aligned with the needs of decadal prediction that are identified as part of the decadal predictability research. Finally, the data assimilation system will be implemented at eddy-resolving scales during the data-rich years of 2006-present, and evaluated with experimental predictions.