Three independent, quasi-global, gridded data sets of precipitation (a rain gauge-based data set, the satellite-only component of the NASA Integrated Multi-satellitE Retrievals for Global Precipitation Measurement mission (IMERG) Final Run precipitation product, and precipitation estimates derived from NASA Soil Moisture Active Passive (SMAP) soil moisture retrievals), are objectively combined into a single pentad precipitation data set at 36-km resolution using a unique approach based on extended triple collocation. The quality of each of the four data sets is then evaluated against independent observations. When a global land surface model at 36-km resolution is integrated four times, once utilizing the merged precipitation forcing and once with each of the three contributing data sets, the near-surface soil moisture variations produced with the merged forcing validate best against independent satellite-based soil moisture fields. In addition, the merged data set is found to be more consistent, relative to each contributor, with estimates of air temperature variations across the globe. The merged data set thus appears to draw successfully on the complementary strengths of each contributor: the particularly high quality of the rain gauge-based data set in areas of high gauge density, the more uniform accuracy across the globe of the IMERG data, and the moderate accuracy, particularly in semi-arid regions, of the soil moisture retrieval-based data.

中文翻译：

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通过合并独立降水数据集改进 Pentad 降水估计

三个独立的准全球网格降水数据集（一个基于雨量计的数据集，美国宇航局全球降水测量任务综合多卫星检索（IMERG）最终运行降水产品的仅卫星组件，以及降水估计源自 NASA 土壤水分主动被动 (SMAP) 土壤水分反演），使用基于扩展三重搭配的独特方法，客观地组合成一个分辨率为 36 公里的单一候级降水数据集。然后根据独立观察评估四个数据集中每一个的质量。当分辨率为 36 公里的全球地表模型被整合四次时，一次利用合并的降水强迫，一次利用三个贡献数据集的每一个，合并强迫产生的近地表土壤水分变化在独立的基于卫星的土壤水分场中得到了最好的验证。此外，发现合并数据集相对于每个贡献者更一致，估计全球气温变化。因此，合并后的数据集似乎成功地利用了每个贡献者的互补优势：在雨量计密度高的地区，基于雨量计的数据集质量特别高，IMERG 数据在全球范围内的准确性更加统一，以及基于土壤水分反演的数据具有中等准确性，尤其是在半干旱地区。估计全球气温变化。因此，合并后的数据集似乎成功地利用了每个贡献者的互补优势：在雨量计密度高的地区，基于雨量计的数据集质量特别高，IMERG 数据在全球范围内的准确性更加统一，以及基于土壤水分反演的数据具有中等准确性，尤其是在半干旱地区。估计全球气温变化。因此，合并后的数据集似乎成功地利用了每个贡献者的互补优势：在雨量计密度高的地区，基于雨量计的数据集质量特别高，IMERG 数据在全球范围内的准确性更加统一，以及基于土壤水分反演的数据具有中等准确性，尤其是在半干旱地区。