GSMaP_Gauge卫星降水数据在流域尺度的精度评估—以白龙江流域为例

以白龙江流域为研究区,利用雨量站和水文站共计27个站点2015年逐日降水资料,分别从日尺度和月尺度定量评估了最新版本(V6)GSMa P__Gauge降水产品精度,并分析其时空特征,通过对探测率、空报率和ETS评分进行空间插值和统计分析,评价了该产品对不同日降水强度阈值下降水事件的探测性能。结果表明:GSMaP__Gauge产品日降水在低海拔湿半年的反演精度良好;月降水模拟值在干半年(10月—次年3月)与站点实测月降水的一致性优于湿半年(4—9月);湿半年月降水反演精度随高程变化差异明显,在低海拔表现为普遍高估月降水,且逐月精度评估结果与高海拔相比偏差大但误差略小,8月精度较优;日降水强度阈值为0 mm·d-1时,产品的探测率在湿半年达到0.9以上,综合空报率和ETS评分来看,在日降水强度阈值为1 mm·d-1时探测性能最优;整体而言,产品在流域西北部高海拔区域对日降水事件探测性能较差,尤其针对较强降水(10 mm·d-1)。

Accuracy Assessment of Gauge-Adjusted Global Satellte Mapping of Precipitation at the Basin Scale:A Case Study in Bailong River Basin

Based on the observation of daily precipitation from 27 stations in Bailong River Basin in 2015, the accuracy of GSMaP_Gauge (version V6) data was assessed quantitatively at daily and monthly scales. And the performance of the product in detecting the rainfall events under different daily precipitation intensities was also evaluated. The results are as follows: (1) The daily precipitation from GSMaP_Gauge and stations indicated better consistency in low altitude area during wet period. (2) The monthly precipitation showed better accuracy in dry period. During wet period, the accuracy was more sensitive to elevation and G_Gauge product generally overestimated monthly precipitation. Assessment for each month showed higher BIAS and lower RMSE in low altitude area, compared with that in high altitude (over 2000m) area, and good accuracy was found in August. (3) G_Gauge products can effectively discriminated rain and non-rain for a day, and the POD reached more than 0.9 during wet period. The optimal detection performance for the basin appeared when precipitation intensity threshold was 1mm/d. High altitude area in the northwest of the basin showed poor detection performance, especially for stronger daily precipitation.