A Twelve-Year Tropical Rainfall Climatology Based on a Composite of TRMM Products

One of the key goals of Tropical Rainfall Measuring Mission (TRMM) has been to define the spatial and seasonal climatological rainfall in the tropics as accurately as possible in order to quantify this key component of the hydrological cycle. To accomplish this goal among many others, TRMM was designed to have both passive (radiometer) and active (radar) microwave instruments. A new climatology of tropical surface rain will be described based on a composite of twelve years (1998-2009) of precipitation products (Version 6) from TRMM. This TRMM Composite Climatology (TCC) consists of a combination of selected TRMM rainfall products over both land and ocean. Bias error estimates derived from the variance among the input products are also described. The impact of the new Version 7 TRMM products, to be available in 2011, will be estimated through comparison of early samples of the Version 7 data.

Comparison with analyses from the Global Precipitation Climatology Project (GPCP) and Modern Era Retrospective-analysis for Research and Applications (MERRA) will also be performed. In addition, a case study of the relationship between surface rainfall and surface temperature in the tropics throughout the recent ENSO cycle (2006-2009) will be presented to understand the differences between the active and passive microwave estimates through this type of event.