Hydrologic Evaluation of the TRMM Multisatellite Precipitation Analysis Over Ganjiang Basin in Humid Southeastern China

Abstract

This study assesses the successive Version-6 and Version-7 TRMM Multisatellite Precipitation Analysis (TMPA) products including near-real-time products (3B42RTV6 and 3B42RTV7) and post-real-time research products (3B42V6 and 3B42V7) from March 2002 to February 2008 over Ganjiang Basin in the humid southeastern China, located in the lower reach of Yangtze River. Direct comparison of TMPA rainfall estimates with ground observation shows that the spatial and temporal rainfall characteristics over this region are well captured by 3B42V6, 3B42RTV7, and 3B42V7. In terms of daily grid-based comparison, 3B42RTV7 has been improved over 3B42RTV6 by reducing relative bias (RB) from -30.25% to 4.93%; 3B42V6, 3B42RTV7, and 3B42V7 show close performance with each other with RB less than 5% and moderate correlative coefficient (CC, 0.59). Daily hydrologic simulation with Xin'anjiang hydrologic model using these TMPA products as input shows that: 1) 3B42V6 and 3B42V7 demonstrate very comparable hydrologic skills, which are close to those of the reference rainfall with high Nash-Sutcliffe index (NSCE, 0.71 and 0.72, respectively) and strong correlation (CC = 0.88); and 2) 3B42RTV7 displays a better hydrologic performance than 3B42RTV6 by increasing the NSCE from 0.56 to 0.59, improving CC from 0.81 to 0.87, and reducing RB from -33.15% to 20.93%. This improvement of real-time TMPA product shows its potential hydrologic utility in water resource management and flood forecast. Finally, this study provides useful reference for TMPA developers and insights for the end users in their applications.