Comparison of the monthly precipitation derived from the TRMM satellite

A comparison of monthly rainfall derived from the version 5 of TRMM Microwave Imager (TMI), Precipitation Radar (PR),TRMM Combined algorithm (TCA) and TMI-emission algorithm (TMIE) using two years (1998 to 1999) of TRMM data was made. The global (TRMM domain, 40 degreesN similar to 40 degreesS) average rain rates are 3.29, 2.62 and 2.93 mm/day over land and 3.02, 2.47 and 2.54 mm/day over oceans for TMI, PR, and TCA respectively. The TMIE oceanic average is 2.90 mm/day. For both the global and zonal means, the TMI rain rates are the largest and the PR estimates lowest. Regression analyses show the offsets of algorithms are close to zero. According to a paired test, significant differences exist between TMI and PR and between TMI and TCA, especially in oceanic dry regions. However, the difference between PR and TCA was judged to be insignificant. Comparison of PR and TMIE shows that a statistically significant difference is evident in the oceanic dry regions.