The Transition in Multi-Satellite Products from TRMM to GPM (TMPA to IMERG)
The transition from the Tropical Rainfall Measuring Mission (TRMM) data products to the Global Precipitation Measurement (GPM) mission products has begun. This document specifically addresses the multi-satellite products, the TRMM Multi-satellite Precipitation Analysis (TMPA), the real-time TMPA (TMPA-RT), and the Integrated Multi-satellitE Retrievals for GPM (IMERG).
TRMM is out of fuel and slowly descending. As well, there are some battery issues. The actual demise of TRMM is not the substantive issue. On 7 November 2014 the satellite descended to an altitude that precluded useful TRMM Precipitation Radar data, although the TRMM Microwave Imager (TMI) will function alone, with slowly changing characteristics until the decommissioning, forecast to be in early 2015. The TMI will continue to be used as one of the input satellite data sets for the TMPA and TMPA-RT, but if quality issues arise, its loss would not be a fatal diminution of the microwave data content.