The GPM is n international satellite mission launched by NASA and JAXA on Feb. 27, 2014. The GPM is a follow-on to TRMM which, after 17 years, officially came to an end on April 15, 2015. In addition to the moderate and heavy rainfall that TRMM was capable of observing in the tropics, GPM also observes light rain and falling snow. Its orbit passes above a larger portion of the world. TRMM’s orbit covered the latitude ranging from 35 degrees north to 35 degrees south, but GPM’s coverage of latitude from 65 degrees north to 65 degrees south stretches nearly to the Arctic and Antarctic Circles.
"The GPM mission is an international network of satellites that provide the next-generation global observations of rain and snow. Building upon the success of the Tropical Rainfall Measuring Mission (TRMM), the GPM concept centers on the deployment of a “Core” satellite carrying an advanced radar / radiometer system to measure precipitation from space and serve as a reference standard to unify precipitation measurements from a constellation of research and operational satellites.
The GPM Core Observatory design is an extension of TRMM which focused primarily on heavy to moderate rain over tropical and subtropical oceans. It carries the first space-borne Ku/Ka-band Dual-frequency Precipitation Radar (DPR) and a multi-channel GPM Microwave Imager (GMI). The DPR instrument, which will provide three dimensional measurements of precipitation structure over 78 and 152 mile (125 and 245 km) swaths, consists of a Ka-band precipitation radar (KaPR) operating at 35.5 GHz and a Ku-band precipitation radar (KuPR) operating at 13.6 GHz. The GMI instrument is a conical-scanning multi-channel microwave radiometer covering a swath of 550 miles (885 km) with thirteen channels."
NASA’s Level 3 Integrated Multi-Satellite Retrievals for GPM (IMERG) gridded product will have a resolution of 0.1 degrees and updated every 30 minutes from 60⁰N-60⁰S. T IMERG ombine precipitation measurements from 9 international satellites: GPM, GCOM-W1, NOAA-18, NOAA-19, DMSP F-16, DMSP F-17, DMSP F-18, Metop-A, and Metop-B. Sample videos are available.
A general history "From TRMM to GPM: The Evolution of NASA Precipitation Data" is an easy read.
The data set source should be acknowledged when the data are used. A formal reference of the form:
<authors>, 2012, last updated 2013: <dataset name>. NASA/GSFC, Greenbelt, MD, USA, NASA Goddard Earth Sciences Data and Information Services Center (GES DISC). Accessed <enter user data access date> at <DOI>
National Center for Atmospheric Research Staff (Eds). Last modified 07 Apr 2017. "The Climate Data Guide: GPM: Global Precipitation Measurement Mission." Retrieved from https://climatedataguide.ucar.edu/climate-data/gpm-global-precipitation-measurement-mission.