The Integrated Multi-satelliE Retrievals for GPM (*IMERG*) is the unified U.S. algorithm that provides the Day-1 multi-satellite precipitation product for the U.S. GPM team. The precipitation estimates from the various precipitation-relevant satellite passive microwave (PMW) sensors comprising the GPM constellation are computed using the 2014 version of the Goddard Profiling Algorithm (GPROF2014), then gridded, intercalibrated to the GPM Combined Instrument product, and combined into half-hourly 0.1°x0.1° fields.
This algorithm is intended to intercalibrate, merge, and interpolate “all” satellite microwave precipitation estimates, together with microwave-calibrated infrared (IR) satellite estimates, precipitation gauge analyses, and potentially other precipitation estimators at fine time and space scales for the TRMM and GPM eras over the entire globe. The system is run several times for each observation time, first giving a quick estimate and successively providing better estimates as more data arrive. The final step uses monthly gauge data to create research-level products.
Learn more: https://pmm.nasa.gov/data-access/downloads/gpm
- The Integrated Multisatellite Retrievals for GPM (IMERG) dataset provides near-realtime global observations of rainfall at 10km resolution, which can be used to estimate total rainfall accumulation from storm systems and quantify the intensity of rainfall and flood impacts from tropical cyclones and other storm systems. (https://pmm.nasa.gov/articles/two-decades-precipitation-measurement)
- IMERG is used by the UMD Global Flood Monitoring System (GFMS) to detect potential flooding conditions and estimate intensity (http://flood.umd.edu/)
- IMERG precipitation data is integrated into the Landslide Hazard Assessment for Situational Awareness (LHASA) model to create landslide "nowcasts" that warn of potential landslide conditions around the world and provide situational awareness of landslide hazards. (https://pmm.nasa.gov/articles/modeling-landslide-threats-near-realtime)