|Coverage||Tropical Oceans (40N-40S, 0-360E)|
|Time Period||December 1997 - Present|
|Resolution||5 x 5 degree, monthly|
A number of climate rainfall products are produced from the passive microwave (TMI) and precipitation radar (PR) sensors on board the Tropical Rainfall Measuring Mission (TRMM) satellite, which was launched in November of 1997. The TRMM monthly or climate rainfall products, referred to as the level 3 products, are derived primarily from accumulations of the TRMM level 2 products, or instantaneous rainfall estimates corresponding to the original satellite snapshot views. The availability of multiple rainfall products from the various TRMM rainfall sensors is due to the fact that each one has various strengths and weaknesses. As a result, the "best" rainfall estimate is application dependent. The TRMM PR provides the highest spatial resolution (~4 km), most information content, the best vertical resolution (80 levels), and the most directly measured surface rainfall estimates for many application. The swath width of the PR, however, is around 1/3 of the TMI swath width resulting is significantly poorer sampling for many climate applications.
The current version is version 6
The 3A11 dataset is computed from the TMI data using an emission-based passive microwave retrieval algorithm developed by Wilheit et al. . Monthly rainfall estimates are computed over ocean regions only using monthly brightness temperature histograms over 5x5 degree lat/lon boxes. For this reason, unlike many of the other TRMM climate rainfall products, there is no corresponding level 2 data as the algorithm is only applied to compute monthly rainfall estimates.