TRMM数据在京津冀地区干旱监测适用性研究

Evaluating the applicability of TRMM data in monitoring drought events in Beijing-Tianjin-Hebei region

基于气象站点实测降水数据和热带降雨卫星(Tropical Rainfall Measurement Mission,TRMM)3B43 Version7(V7)降水产品,计算了京津冀地区1998-2017年多时间尺度标准化降水指数(standardized precipitation index,SPI)(SPI-1、SPI-3、SPI-6和SPI-12)。结果表明:TRMM 3B43数据与站点观测月和年降水数据在时空上具有良好的一致性;从时间变化趋势来看,基于TRMM 3B43数据和站点降水数据计算的不同时间尺度的SPI值存在高度一致性;从空间变化趋势来看,基于两种数据计算的京津冀地区25个站点多时间尺度SPI的相关系数均大于0.7,POD值大于0.6,80%以上的FAR值小于0.3,70%以上站点的FBI值在0.9~1.1之间;两种数据计算的干旱的面积百分比基本一致,1、3、6和12个月的干旱面积的CC值分别为0.93、0.95、0.96和0.96。

The standardized precipitation indexes(SPI,including SPI-1,SPI-3,SPI-6,and SPI-12)at multi-temporal scales from 1998 to 2017 in Beijing-Tianjin-Hebei region were calculated based on the monitored precipitation data of meteorological stations and Tropical Rainfall Measuring Mission(TRMM)V73 B43 products.The results showed that the monthly and annual precipitation data of TRMM 3 B43 products were consistent with that of the meteorological stations in Beijing-Tianjin-Hebei region in terms of time variation and space distribution.The SPI calculated by these two data sources agreed quite well at different time scales.In terms of spatial distribution,the SPI based on monthly TRMM3 B43 data showed a consistent variability compared with the actual monitored data of the 25 stations.The values of correlation coefficients were more than 0.7 and probability of detection(POD)values were more than 0.6.More than 80%of the false alarm ratio(FAR)values were less than 0.3,and more than 70%of the stations had frequency bias index(FBI)values ranging from 0.9 to 1.1.Moreover,the mean drought area percentage calculated by these two data sources matched well,and the Pearson correlation coefficient(CC)values were 0.93,0.95,0.96,and 0.96 at the different time-scales(SPI-1,SPI-3,SPI-6,and SPI-12),respectively.