Import TRMM

TRMM data are usually delivered in a specific HDF format which is (partially) supported from GDAL 1.8+ (so, r.in.gdal would in theory work).

However, it is easier to get binary grids from here

ftp://disc2.nascom.nasa.gov/data/TRMM/Gridded/3B43_V6/

The format is explained here. Hence, to import gridded TRMM into a Lat-long location with is done via

# generally
r.in.bin -f -b north=50 south=-50 east=180 west=-180 rows=400 cols=1440 ....

e.g.

r.in.bin -f -b input=3B43.100101.6.precipitation.bin output=3B43.100101.6.precipitation \
         north=50 south=-50 east=180 west=-180 rows=400 cols=1440

Optionally convert then to mm/hr to some other time unit.