Abstract:
Shaanxi Qinling-Daba Mountains is a typical area which has a complicated terrain. In this area, the study chose the data from 23 rain gauge stations to validate the accuracy of TRMM 3B42 (tropical rainfall measuring mission) precipitation product data over the period of 1998—2014 at different time scales and different terrain region, and evaluated the detecting the occurrence of rainy events for TRMM 3B42 daily precipitation. The results showed that TRMM 3B42 precipitation product had a higher accuracy in the annual, month and quarter timescale, and the accuracy is not good enough in the daily timescale. It showed good performance for detecting the occurrence of rain events with average equitable threat score(SET) of 0.38 in each rain gauge station. TRMM precipitation change process was consistent with the observed precipitation, but there were some differences in precipitation values. From May to October, there was a certain overestimation in the basin area, and some underestimation in the mountain region.The range of overestimation and underestimate was both less than 10%. In the dry season rainfall, TRMM precipitation had a good fit with the observed. Moreover, altitude and average annual precipitation had impacts on data accuracy. The absolute error of precipitation decreased and yet the ability of detecting rain events became weak with the increasing altitude，while the effect of average annual precipitation on data accuracy was opposite.
