TRMM卫星降水产品在尼洋河流域的适用性定量分析

Quantitative analysis on the applicability of TRMM satellite precipitation products in the Niyang River Basin

作为地面雨量站资料的重要补充,卫星降水产品对资料短缺或无资料地区尤为重要。位于我国高寒山区的尼洋河流域属于典型的资料短缺地区,根据5个气象站点2001-2016年的月降水数据和中国地面降水日值格点数据集2001-2013年的日降水资料,利用反距离权重插值法对其进行处理,在尼洋河流域分别对月、日尺度数据用相关系数(R)和相对误差(BIAS)检验TRMM降水数据的精度。结果表明:在时间尺度上,TRMM月降水数据与实测数据在流域整体上一致性良好(R=0. 90),而日降水数据的一致性较差(R=0. 29),且BIAS较大;在单一站点上,TRMM月降水数据的精度较高(R> 0. 9),而日尺度R <0. 50,精度较低。在空间尺度上,通过克里金插值法得到TRMM降水精度的空间分布,月降水精度由西向东逐渐减小,而日降水的精度与之相反。整体上,TRMM月降水数据精度高,具有较好的适用性,根据TRMM月降水数据分析尼洋河降水时空分布特征。结果显示尼洋河流域降水大都集中在5月至9月,而11月至次年2月,降水量很少;年降雨量呈现由西北向东部逐渐递增的趋势,不同区域降水量差异较大。

As an important supplement to the ground observation data,satellite precipitation products are of particularly important for areas lack of data or without data. The Niyang River Basin in the arctic-alpine mountainous region of China is a typical area that of data shortage. Based on the precipitation data of the five meteorological stations from 2001 to 2016 and the China ground precipitation daily grid point dataset from 2001 to 2013,the inverse distance weighted interpolation method was employed to process the precipitation data. The accuracy of TRMM precipitation data was estimated by correlation coefficient( R) and relative error( BIAS) at monthly and daily scales in the Niyang River Basin. The results showed that the monthly precipitation data of TRMM and the measured data had good consistency in the whole basin( R = 0. 90),but the consistency was poor and BIAS was large for the daily precipitation data( R = 0. 29). For the single station,the accuracy of TRMM monthly precipitation data was high( R> 0. 9),while the R of the daily scale were less than 0. 5 and the precision was low. On the spatial scale,the spatial distribution of the accuracy of TRMM precipitation was obtained by Kriging interpolation method. The accuracy of monthly precipitation decreased from west to east,while the accuracy of daily precipitation illustrated an opposite trend. Based on the high precision of TRMM monthly precipitation data,the temporal and spatial distribution characteristics of precipitation in the Niyang River were analyzed. The results showed that most of the precipitation in the Niyang River basin was concentrated from May to September,and less precipitation happened from November to February. The annual rainfall showed an increasing trend from northwest to east,and the precipitation varied greatly in different regions.