GPM IMERG

IMERG (Integrated Multi-satellitE Retrievals for GPM) merges the GPM satellite constellation's passive microwave and infrared observations into a global precipitation grid at 0.1° and half-hourly resolution, with a continuous record extending back to 1998 by splicing in the earlier TRMM mission. Early and Late runs arrive within hours for near-real-time monitoring; the Final run adds gauge correction weeks later for analysis-grade accuracy.

Its temporal resolution makes it the satellite product of choice for flash-flood and urban-drainage work, where CHIRPS's daily timestep is too coarse — at the cost of finer spatial detail than CHIRPS's gauge-anchored 0.05° grid.