Collaborative Research: Type 1 L02170226: Developing and Implementing Ocean-Atmosphere Reanalyses for Climate Applications (OARCA)

本研究将发展新的具有量化不确定性的海洋和大气再分析，以解决自1871年以来观测到的气候变率和变化领域的几个未解决的问题。这项工作包括发展一系列数值模式，从而形成一个新的再分析系统，称为OARCA（海洋大气再分析用于气候应用），用于了解全球和区域气候变化和变率。数据同化系统基于两个现有的再分析：大气的20世纪再分析系统（20CR）和全球海洋的简单海洋数据同化系统（SODA）。OARCA的工作依赖于NCCS和DOE NERSC的高性能大规模并行平台来进行再分析。它的生产将推进如何有效地计算非常大的地球物理系统的知识。由此得出的1871年至2008年期间气候系统的状态估计将用于探索年代际变率模式，其中包括热带太平洋环流的变化和大西洋经向翻转环流的变率。这些重新分析还将帮助我们更好地理解气候现象的年代际变化，如干旱周期、厄尔尼诺Niño、北美和亚洲季风，以及飓风活动的低频变化。更广泛的意义和重要性对气候系统的状态评估结果将通过位于德州农工大学、NOAA地球系统研究实验室和科罗拉多大学CIRES气候诊断中心的数据服务器进行分发。研究人员将能够将这些数据用于他们自己的气候变率和气候变化研究，范围从极端天气统计到年代际变率和长期趋势。除了利用再分析诊断20世纪的气候变率外，状态估计还可用于区域降尺度和年代际预测模式的初始条件和边界条件。OARCA的数据集将为测试和评估气候预测模型提供具有量化不确定性的基准和度量，从而对有意改进地球系统模型的研究人员非常有用。新的再分析将为研究界提供具有状态相关误差条的SST（海表温度）分析，可作为AR5气候模式长期区域趋势和变率的客观验证。

Technical DescriptionThis research will develop new oceanic and atmospheric reanalyses with quantified uncertainties to address several unresolved questions in the area of observed climate variability and change since 1871. The work involves developing a hierarchy of numerical models resulting in a new reanalysis system called OARCA (Ocean Atmosphere Reanalysis for Climate Applications) to be used for understanding global and regional climate change and variability. The data assimilation system is based on two existing reanalyses: The Twentieth Century Reanalysis system (20CR) for the atmosphere and the Simple Ocean Data Assimilation system (SODA) for the global oceans. The OARCA effort relies on high performance massively parallel platforms such as those at NCCS and DOE NERSC to produce the reanalyses. Its production will advance the knowledge of how to efficiently compute very large geophysical systems. The resulting state estimates of the climate system for the period 1871 to 2008 will be used to explore modes of decadal variability that include changes in the tropical Pacific circulation and variability of the Atlantic Merdional Overturning Circulation. These reanalyses will also help us better understand the decadal variability of climate phenomena such as drought cycles, El Niño, North American and Asian monsoons, and the low frequency variability of hurricane activity.Broader Significance and ImportanceThe resulting state estimate of the climate system will be distributed via data servers at Texas A&M and at the NOAA Earth System Research Laboratory and University of Colorado CIRES Climate Diagnostics Center. Researchers will be able to use these data for their own studies of climate variability and climate change that range from the statistics of weather extremes to decadal variability and long-term trends. In addition to using the reanalysis to diagnose climate variability in the 20th Century, the state estimation will be available to be used for initial and boundary conditions for regional downscaling and decadal prediction models. The OARCA datasets will be useful to researchers interested in improving Earth System models by providing benchmarks and metrics with quantified uncertainties for testing and evaluating climate prediction models. The new reanalyses will provide to the research community SST(Sea Surface Temperature) analyses with error bars that are state dependent, which can be used as an objective verification of climate model AR5 regional trends and variability over long periods.