Accuracy and spatio-temporal variation of high resolution satellite rainfall estimate over the Ganjiang River Basin

Abstract

Based on spatial interpolation rainfall of the ground gauge measurement, we proposed a method to comprehensively evaluate and compare the accuracy of satellite rainfall estimates (SREs) at three spatial scales: 0.25°×0.25° grid scale, sub-catchment scale and the whole basin scale. Using this method, we evaluated the accuracy of six high-resolution monthly SREs (TRMM 3B42 V6, 3B42RT V6, CMORPH, GSMaP MWR+, GSMaP MVK+ and PERSIANN) and revealed the spatio-temporal variation of the SRE accuracy based on spatial interpolated rainfall from a dense network of 325 gauges during 2003–2009 over the Ganjiang River Basin in the Southeast China. The results showed that ground gauge-calibrated 3B42 had the highest accuracy with slight overestimation, whereas the other five uncalibrated SREs had severe underestimation. The accuracy of the six SREs in wet seasons was remarkably higher than that in the dry seasons. When the time scale was expanded, the accuracy of SRE, particularly 3B42, increased. Furthermore, the accuracy of SREs was relatively low in the western mountains and northern piedmont areas, while it was relatively high in the central and southeastern hills and basins of the Ganjiang River Basin. When the space scale was expanded, the accuracy of the six SREs gradually increased. This study provided an example for of SRE accuracy validation in other regions, and a direct basis for further study of SRE-based hydrological process.