Validation of Diurnal Cycle and Intra-seasonal Variability of TRMM Satellite Rainfall

The version 6 TRMM rainfall products showed significant improvements on satellite rain retrievals as compared to rain gauge observations. The differences between TRMM TMI rain products and gauge observations are less than 10% over Florida, Texas, Kwajalein, and Darwin ground validation sites for the 8-year period from January 1998 to December 2005. The rain differences between Version 6 TMI and PR data are also within 10% over these GV sites except the Darwin area. The diurnal cycle from 8-years TRMM TMI and PR rain data showed peaks in the early morning over ocean and in the early afternoon over land. These results are accurate as compared to the gauge statistics over TRMM ground validation sites and other ground observations. TRMM TMI rain products indicate that variances of diurnal cycle are less than 5% of intra-seasonal variances over tropical oceans. Parallel spectrum analyses on TMI and Global Precipitation Climatology Project (GPCP) rain products indicate a near-perfect match of intra-seasonal spectral distributions over tropical oceans. DOI: 10.2529/PIERS060831112605