Chang SSM/I Derived Monthly Rain Indices 5 x 5 degree V2.3 (RAIN_CHANG) at GES DISC
These data are transitioned to a state of permanent preservation. They are available upon request.
More advanced datasets have been developed since. 
One recommended replacement is the GPCP (doi: 10.5067/DBVUO4KQHXTK) product developed under the MEaSUREs project.

Futhermore, the NASA Precipitation Measurement …