TRMM/ GPM卫星降水产品在淮河上游逐日和小时尺度的精度评估

基于淮河流域上游区(洪河口以上) 2014年4月-2015年12月的实测逐日和小时降水数据,采用综合评价指标评估了TRMM 3B42 v7和GPM IMERG卫星产品在逐日和小时尺度上的监测精度。结果表明:逐日尺度上,对于流域面平均降水和网格降水,GPM产品与实测降水的相关性略优于TRMM,相关系数为0. 87,误差略大于TRMM,但均控制在0. 8 mm/d以内;降水探测能力方面,GPM与实测降水的一致性较高,尤其表现在小雨和中雨降水事件上,可用于日尺度的水文模拟和水资源评价等研究。小时尺度上,TRMM对6场极端降水的监测能力比较稳定,略有低估(BIAS均值为-6%),GPM对不同的极端降水事件监测能力不一,可靠性相对较低,相对于TRMM卫星降水产品,GPM在对极端降水的监测能力方面还有待提高。

Accuracy evaluation of TRMM /GPM satellite precipitation products on daily and hourly scales in upper reaches of Huaihe River Basin

Based on the gauge-based daily and hourly precipitation data from April 2014 to December 2015 in the upper reaches of Huaihe Basin (above Honghekou estuary), the comprehensive evaluation indices were used to evaluate the monitoring accuracy of TRMM 3B42 v7 and GPM IMERG in the daily and hourly scales. The results show that: on the daily scale, the correlation between GPM product and gauge-based precipitation is slightly better than TRMM with correlation coefficient 0.87, and the error is slightly larger than that of TRMM, but both are controlled < 0.8 mm/d. In terms of precipitation detection capability, the consistency between GPM and gauge-based precipitation is significantly improved, especially in light and moderate precipitation events, which shows that GPM product can be used for hydrological simulation and water rescources evalution on the daily scale. At the hourly scale, the monitoring capacity of TRMM for six extreme precipitation events is relatively stable, slightly underestimates ( BIAS average is -6% ). However, the reliability of GPM for different extreme precipitation events is lower, indicating that the monitoring accuracy of GPM product in extreme precipitation needs to be improved.