The monthly data set consists of two files containing global monthly averaged precipitation rate values at a 2.5x2.5 resolution
starting in 1979. Values are obtained from 5 kinds of satellite estimates (GPI,OPI,SSM/I scattering, SSM/I emission and MSU).
The enhanced file also includes blended NCEP/NCAR Reanalysis Precipitation values. The other just includes the satellite estimates.
Pentad data is also available.
Xie, P., and P.A. Arkin, 1997: Global precipitation: A 17-year monthly analysis based on gauge observations, satellite estimates,
and numerical model outputs. Bull. Amer. Meteor. Soc., 78, 2539 - 2558.