Dynamic Reassimilation of Atmospheric Observations for Global Climate Change Studies: A Feasibility Study

pi将产生1982年5月至1983年11月期间全球大气的四维内部一致网格数据集。为此，他们将收集这一时期最完整的一套大气和海洋观测资料，并使用最先进的多变量最优插值方案进行大气资料同化。这项工作的主要动机是证明利用最先进的全球模式和全球数据同化系统重新分析过去大气观测的可行性。在为气候研究制定重新分析长期（10年）历史数据集的计划之前，需要进行这样的可行性研究。所使用的资料同化系统将包括COLA一般环流模式，其预报将提供第一个猜测和最准确的最佳插值算法。观测数据将是在此期间实时存档的二级数据和延迟模式数据的组合，包括在NCAR组装的综合海洋-大气数据集（COADS）。对分析的关键性评价将包括一般流通统计；全局和局部能谱；全球能量诊断包括能量的产生和耗散；对全球水文循环的详细研究，包括热带太平洋、北美、亚马逊河流域和撒哈拉以南非洲的区域预算；以及地表风应力和总热通量的计算，以迫使全球海洋模式。pi将存档同化周期中获得的各种分析误差测量，以研究分析的质量，并提供置信度估计和误差条。该研究对支持热带海洋全球大气（TOGA）、世界海洋环流实验（WOCE）、全球能量和水循环实验（GEWEX）和国际地圈生物圈计划（IGBP）等国家和国际研究项目的科学目标具有重要意义。国家海洋局选择1982- 83年这一时期进行这项研究，是因为它见证了厄尔尼诺-南方涛动现象及其相关的全球影响所体现的海洋-大气相互作用的最突出的例子。

The PIs will produce a four-dimensional internally consistent gridded data set for the global atmosphere for the period May 1982 to November 1983. They will do so by assembling the most complete set of atmospheric and oceanic observations made during that period and by using a state-of-the-art multivariate optimal interpolation scheme for atmospheric data assimilation. The primary motivation or this work is to demonstrate the feasibility of reanalyzing past atmospheric observations using a state-of-the-art global model and a global data assimilation system. Such a feasibility study is needed before making plans for reanalysis of long term ( 10 years) historical data sets for climate research. The data assimilation system to be used will include the COLA general circulation model, the forecast of which will provide the first guess, and most accurate optimum interpolation gorithm available. The observational data se will be a combination for level II-data archived in real time during the period and delayed mode data, including the comprehensive Ocean-Atmosphere Data Set (COADS), which have been assembled at NCAR. The critical evaluations of the analyses will include general circulation statistics; global and local energy spectra; global energetic diagnoses including generation and dissipation of energy; a detailed examination of the global hydrologic cycle including regional budgets for the tropical Pacific, North America, the Amazon basin, and sub-Saharan Africa; and computations of surface wind stress and total heat flux to force a global ocean model. The PIs will archive the various measures of analysis error obtained during the assimilation cycle to study the quality of the analyses and to provide confidence estimates and error bars. This study will be extremely useful to support the scientific objectives of national and international research programs such as the Tropical Oceans Global Atmospheric (TOGA), World Ocean Circulation Experiment (WOCE), Global Energy and Water Cycle Experiment (GEWEX) and International Geosphere Biosphere Program (IGBP). The PIs have chosen the 1982--83 period for this study because it witnessed the most outstanding example of ocean- atmosphere interactions as manifested by the El Nino-Southern Oscillation phenomenon and its related world-wide effects.