MSWEP降水产品在中国大陆区域的精度评估

Accuracy assessment of MSWEP over China's Mainland

基于1979—2015年中国大陆824个气象站点逐日降水观测资料,采用相对误差、相关系数以及探测率等指标,评估新发布的格网化降水产品Multi-Source Weighted-Ensemble Precipitation(MSWEP)在中国大陆区域的精度;采用改正的Mann-Kendall趋势法,对比分析MSWEP在降水量趋势分析中的可靠性。研究表明:(1)MSWEP对中国大陆区域降水整体上存在高估现象,而在华北区域存在低估现象;(2)MSWEP对微量降水和强降水事件分别存在高估和低估现象;(3)MSWEP和降水资料在年和月尺度上具有较好的相关系数,在日尺度上相关系数较低;(4)MSWEP和站点观测的年降水量变化趋势存在较大空间分布差异,但在春季、秋季和冬季,空间分布特征较为一致。

The accuracy assessment of global gridded precipitation products is the first step in local application. Based on the daily precipitation observation data of 824 weather stations in China during 1979—2015,this study intends to evaluate quantitatively the accuracy of newly released Multi-Source Weighted-Ensemble Precipitation（ MSWEP） products in China by using a variety of indicators such as relative bias and correlation coefficient. Moreover,a corrected Mann-Kendal trend monitoring method was used to analyze the reliability of MSWEP products in trend analysis of precipitation. The main conclusions show that：（1） Precipitation estimated from MSWEP is higher than that of the gauged precipitation in China. However,there is an underestimate in the North China region.（2） MSWEP daily rainfall data have overestimation and underestimation of slight-precipitation and heavy-precipitation events,respectively.（3） There is a good relation between monthly/annual gauge precipitation and MSWEP.（4） There is an obvious spatial difference between the trends of annual precipitation based on MSWEP and site observations in China. However,in spring,autumn and winter,the spatial distribution of the trend is in good agreement.