2A Radiometer (GPROF & PRPS)
The 2A GPROF and 2A PRPS algorithms estimate precipitation rate from single orbits brightness temperature data from passive-microwave radiometers. The algorithms also uses ancillary information about Earth’s atmosphere and surface. The GPM archive contains 2A GPROF granules for the following instruments, whose satellite names are stated in parentheses in the following list: GMI (GPM), TMI (TRMM), SSMI (F11 through F15), SSMIS (F16, F17, F18), AMSUB (NOAA 16, 17, 18), AMSRE (Aqua), AMSR2 (GCOM W1), MHS (NOAA 18, 19, and 20; METOP A, B, C), and ATMS (NPP). The PRPS algorithm is run on the SAPHIR observations from the Megha-Tropiques satellite.
For instruments currently in orbit, there are near-realtime (NRT) products and standard-research products. All instruments have climate products that are designated 2A-CLIM GPROF or 2A-CLIM PRPS. The difference between climate products and standard-research products is that climate products use ancillary data that are not produced until approximately 3 months after the satellite observations are made.