This FAQ document provides information specifically aimed at the Integrated Multi-satellitE Retrievals for GPM (IMERG) Version 07 for applications users. As of August 2024, both Initial Processing (IP) and retrospective processing (RP) for the IMERG Early, Late and Final products have been completed for Version 07. IMERG V07 involves a wide range of changes to all aspects of the product, many of which are implemented in response to feedback on V06, which was the first time the IMERG record spanned the TRMM and GPM eras.

This document describes the algorithm and processing sequence for the Integrated Multi-satellitE Retrievals for the Global Precipitation Measurement (GPM) mission (IMERG). 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 Tropical Rainfall Measuring Mission (TRMM) and GPM eras over the entire globe.

The algorithm for the Integrated Multi-satellitE Retrievals for GPM (IMERG) has now been upgraded to Version 07.  IMERG V07 involves a wide range of changes to all aspects of the algorithm, many of which are implemented in response to feedback on V06, which was the first time the IMERG record spanned the TRMM-GPM eras.  IMERG V07 is being reprocessed for the entire TRMM-GPM record and thus supersedes all prior IMERG versions, as well as superseding the prior TRMM-based TMPA products (3B42, 3B43).