新疆夏季降水时空分布的适用性评估

Evaluation of summer precipitation of CFSR, ERA-Interim and MERRA reanalyses in Xinjiang

新疆气象站点稀疏且分布不均,高精度时空气象数据缺乏。基于数据同化的再分析资料,可成为解决这一问题的有效途径。利用美国国家环境预报中心再分析数据(CFSR)、欧洲中期数值预报中心再分析数据(ERA-Interim)和美国国家航空航天局再分析数据(MERRA)中的降水数据,分别与1979-2007年新疆气象观测数据和日本气象厅高分辨率亚洲陆地降水数据(APHRO)进行数理统计分析,评估了这3套再分析数据在新疆的适用性。3套再分析数据可有效表征新疆大部分地区年内降水的时空分布特征,夏季降水偏差小于100%;但未能捕捉到夏季降水的长期趋势。夏季降水的偏差与高程具有显著的相关性,这可为订正3套再分析数据、提高降水数据的精度提供技术支撑。

With scarcely and unevenly distributed meteorological stations, Xinjiang is in short of high tempo-spatial resolution climatological data. The reanalysis data which are based on data assimilation can efficiently bridge this gap. The precipitation data of NCEP Climate Forecast System Reanalysis （NCEP CFSR）, European Center for Medium-Range Weather Forecasts （ECMWF） reanalysis ERA-Interim products and Modern Era Retrospective Analysis for Research and Applications （MERRA） were evaluated by statistical analysis based on the meteorological stations data of Xinjiang in 1979-2007 and Asian Precipitation-Highly Resolved Observational Data Integration Towards Evaluation of Water Resources （APHRODITE） respectively. The tempo-spatial pattern of inner-annual precipitation can be effectively characterized by the aforementioned reanalysis datasets in most parts of Xinjiang. And the biases of summer precipitation were less than 100%. However, the long-term tendency of summer precipitation was not captured by reanalysis datasets. Furthermore, significant correlation occurred between summer precipitation bias and elevation, which can be used to rectify and improve summer precipitation data accuracy of the three reanalysis datasets in Xiniiang.