IMERG和GSMaP卫星降水产品在三江源区的适用性评估

Applicability Evaluation of IMERG and GSMaP Satellite Precipitation Data in the Three-River Source Region

利用98个三江源区国家级气象站和区域气象站降水观测资料,对IMERG和GSMaP两种卫星降水产品进行了对比验证分析,并就长江流域、黄河流域和澜沧江流域分别进行了适用性评估。结果表明:IMERG卫星降水产品与地面观测日降水数据的相关系数中位数达到0.62,均方根误差中位数为4.24 mm,命中率能够达到0.80以上,明显优于GSMaP数据;两种卫星降水产品对小雨等级降水略有高估,而对于中雨和大雨均为低估,尤其对于大雨的低估现象更为严重,其中IMERG对短时强降水的低估是造成大雨低估的主要原因之一;两种卫星降水产品平均相关系数均呈现出随着海拔高度升高而降低的特征,且在低海拔区的相关系数最大,均方根误差最小。

Based on the precipitation observation data of 98 national and regional meteorological stations in the Three-River Source Region,compared the precipitation products of IMERG and GSMaP satellites,and the applicability assessment was carried out according to the Yangtze River Basin,the Yellow River Basin and the Lancang River Basin.The results show that the median correlation coefficient between IMERG satellite precipitation products and daily surface precipitation observation data is 0.62,the median root mean square error is 4.24mm,and the hit rate can reach more than 0.80,which is obviously better than GSMaP data.The two satellite precipitation products slightly overestimate the precipitation of light rain,but underestimate the precipitation of moderate rain and heavy rain,especially the underestimation of heavy rain.The IMERG underestimate the short-term heavy rainfall,which is the main reason for the underestimation of heavy rain.The average correlation coefficient of the two precipitation satellite products decreases with the increase of the altitude,and the correlation coefficient is the largest in the low altitude area,and the root mean square error is the smallest.