|Coverage||Global tropics (40N-40S, 0-360E)|
|Time Period||December 1997 - Present|
|Resolution||0.5 x 0.5 degree, instantaneous (overpass)|
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
3G68 is an hourly gridded text (ascii) product containing TRMM 2A12 [Kummerow etal., 2001], 2A25 [Iguchi et al., 2000], and 2B31 [Haddad et al., 1997a, 1997b], rain estimates. The 3G68 product includes 24 hour of hourly grids into a single daily file. The combination of the rain estimates on a common 0.5 x 0.5 degree grid provides an easy way to compare instantaneous results from the three retrieval algorithms. Note that this is not a standard TRMM product
This dataset is available via anonymous ftp at ftp://trmmopen.gsfc.nasa.gov/pub