AGS-PRF: Inferring Predictability and Dynamics of Atlantic Multidecadal Climate Variability from Marine and Terrestrial Paleoclimate Records

在AGS-PRF(博士后研究奖学金)征集的支持下，研究人员的目标是利用最新的代理记录汇编来表征北大西洋海洋表面温度(SSTs)的数十年变化(AMV)。这项研究探索了公开可用的古气候记录与成熟的建模技术相结合的潜力，以解决关于大西洋数十年变率(AMV)的时间尺度、平稳性、人为影响和大气-海洋耦合动力学的基本假设。该项目以三个具体的科学问题和一个影响深远的总体问题为指导。具体地说，这项研究试图解决：问题1)代理记录所证明的AMV的可预测性是什么？代理记录是否暗示了大气-海洋AMV的耦合机制？战略：为了从代理记录中诊断AMV的可预测性，将从海洋和陆地的代理记录中导出线性逆模型(LIM)。特征值分析将用于显示主要的动力模式和时间尺度，海洋和陆地记录将用于识别耦合的气候变异性。我们将比较从替代物、现代观测和最后千年再分析项目的输出中得出的模型的预测技巧。问题2)AMV是否随时间而变化，我们是否可以将变化归因于人为的强迫？策略：AMV的非平稳性，包括对人为影响的可能反应，将通过统计检验、小波分析和在数据的时间子集上构建的LIM的特征向量分析来探索。问题3)一般环流模型和代理衍生模型中的AMV动力学有何不同？策略：在代理派生的LIM中负责AMV的动力学将与CMIP5(耦合模式相互比较项目，阶段5)档案中控制AMV的机制进行比较。这项研究是由一个深远而重要的问题指导的：问题：古气候代理数据是否有能力约束AMV的动力学和可预测性？战略：如果答案是肯定的，那么代理记录可以直接用于做出和评估现代气候预测，并且该技术可以扩展到其他地区和时间尺度。如果答案是否定的，那么这项研究将有助于量化替代记录的限度，以评估现代气候的可预测性，并确定新的记录类型和地点，以提高对动力学的理解和预测能力。更广泛的影响包括支持早期职业科学家，帮助减少北大西洋海洋表面温度(SST)的十年变率(AMV)的不确定性，以及通过大学现有的项目向当地STEM高中教师和学生提供材料。

Under the aegis of the AGS-PRF (post-doctoral research fellowship) solicitation, the researcher aims to leverage recent compilations of proxy records to characterize North Atlantic multidecadal variability (AMV) in sea surface temperatures (SSTs). The research explores the potential of publicly available paleoclimate records in combination with a proven modeling technique to address fundamental hypotheses about the time scales, stationarity, anthropogenic influence, and coupled atmosphere-ocean dynamics of Atlantic multidecadal variability (AMV). The project is guided by three specific science questions and one far-reaching and overarching question. Specifically, the research seeks to address: Question 1) What is the predictability of AMV as evidenced by proxy records? Do proxy records suggest mechanisms of coupled atmosphere-ocean AMV?Strategy: To diagnose AMV predictability from proxy records, linear inverse models (LIMs) will be derived from marine and terrestrial proxy records. Eigenvalue analyses will be used to show dominant dynamical patterns and time scales, and marine and terrestrial records will be used to identify coupled climate variability. Forecast skill of models derived from proxies, modern observations, and output from the Last Millennium Reanalysis Project will be compared.Question 2) Is AMV changing through time, and can we attribute changes to anthropogenic forcing? Strategy: Non-stationarities in AMV, including possible responses to anthropogenic influences, will be explored using statistical tests, wavelet analyses, and eigenvector analyses of LIMs constructed over temporal subsets of the data.Question 3) How do AMV dynamics in general circulation models and proxy-derived models differ? Strategy: Dynamics responsible for AMV in proxy-derived LIMs will be compared to mechanisms for AMV in controls runs from the CMIP5 (Coupled Model Intercomparison Project, Phase 5) archives.The research is guided by the far-reaching and overarching question: Question: Do paleoclimate proxy data have power to constrain AMV dynamics and predictability? Strategy: If "yes," then proxy records can be directly useful in making and evaluating modern climate forecasts, and the techniques can be expanded to other regions and time scales. If "no," then the research will help quantify the limits of proxy records to assess predictability of modern climate, and identify new record types and sites to improve dynamical understanding and predictive power.The broader impacts involve supporting an early career scientist, helping reduce the uncertainty in North Atlantic multidecadal variability (AMV) in sea surface temperatures (SSTs), and providing materials to local STEM high school teachers and students through projects already in existence at the university.