Collaborative Research: Common Era Climate Variability from Marine Proxy Surrogate Reconstructions

密度驱动的大西洋纬向翻转环流（AMOC），它可以影响区域和全球尺度的气候，是很难约束的简短的观测记录。这给现代气候趋势的解释和未来变化的预测增加了相当大的不确定性。拟议的工作将通过在耦合海洋-大气环流模式（AOGCM）模拟的物理一致框架内生成过去2,000年AMOC变化的定量重建来扩展仪器记录。该项目将确定从代用数据中出现的AMOC变异的重要模式及其最可能的原因。合成伪代理将被用来评估这些结果的技能，并确定网站，可能会减少未来的不确定性。这项工作的结果将为自然AMOC-气候关系提供有价值的基线，为最近的趋势提供背景，为未来的气候变化预测提供信息。这项研究将结合联合收割机的海洋代理记录网络跨越过去两千年，在第一阶段的PAGES海洋2K倡议，与气候模式相互比较项目（CMIP）同位素启用AOGCM估计AMOC使用代理替代重建（PSR）。PSR方法中的不确定性所产生的方法选择，数据类型，代理分布和观测误差将进行评估，部分基于伪代理实验（PPE）。PSRs代表完全一致的物理系统，允许AMOC强度和模式在熟练的PSRs与大气环流，外部辐射强迫和其他变量进行比较，以评估其动力学联系。随着未来代理网络的扩大，对PSR的信心可能会增加，PPE将用于确定更多的位置，从这些位置获得更多的数据可能会减少基于PSR的AMOC（和其他变量）估计值的不确定性，为未来的工作提供目标。除了推进国际Oceans 2K和模型相互比较项目工作的更广泛的科学相关性外，其他显着的影响包括支持早期职业研究人员，没有事先获得NSF的支持，本科生的研究机会，以及研究人员参与当地少数民族和高中生的教育计划。

The density-driven Atlantic meridional overturning circulation (AMOC), which can influence climate on regional and global scales, is poorly constrained by brief observational records. This adds considerable uncertainty to the interpretation of modern climate trends and to forecasts of future change. The proposed work will extend the instrumental record by generating quantitative reconstructions of AMOC variability over the past 2,000 years within the physically consistent framework of coupled ocean-atmosphere general circulation model (AOGCM) simulations. The project will identify the significant patterns of AMOC variability that emerge from proxy data and their most likely causes. Synthetic pseudoproxies will be used to evaluate the skill of these results and identify sites that might reduce uncertainty in the future. Results from this work will provide a valuable baseline for natural AMOC-climate relationships, giving context to recent trends that will inform future climate change forecasts. The research will combine a network of marine proxy records spanning the past two millennia, compiled during Phase 1 of the PAGES Ocean2K initiative, with Climate Model Intercomparison Project (CMIP) isotope enabled AOGCMs to estimate AMOC using proxy surrogate reconstructions (PSRs). The uncertainty in the PSR method arising from methodological choices, data type, proxy distribution and observational error will be evaluated based, in part, on pseudoproxy experiments (PPEs). PSRs represent completely consistent physical systems, allowing AMOC strength and pattern in skillful PSRs to be compared with atmospheric circulation, external radiative forcing and other variables to evaluate their dynamical links. Confidence in PSRs will likely increase as the proxy network expands in the future, and a PPE will be used to identify additional locations from which additional data might reduce the uncertainty in PSR-based estimates of AMOC (and other variables), providing a target for future work. In addition to the broader scientific relevance of advancing the international Oceans2K and model intercomparison project efforts, other notable impacts include support of an early career researcher with no prior NSF support, research opportunities for undergraduates, and involvement of both researchers in local education initiatives for minorities and high school students.