Documents

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.

These climatology products contain the daily and “grand” climatological precipitation from the Integrated Multi-satellitE Retrievals for GPM (IMERG) 07B in netCDF4 and GeoTIFF formats. The IMERG Daily Climatology product is derived from the daily precipitation data by averaging the non-missing precipitation values in every 0.1° grid box for a specific day of the year, over a range of years.

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).

This document describes the GeoTIFF translation of a precipitation climatology based on Version 7 Final IMERG. Click here to view the full documentation for the IMERG V07 Daily and Grand Climatology Products.

This document describes the basic idea of DPR data processing. It was originally written for the algorithm used in the at-launch version (V03). The algorithm has been modified and improved since then. Although the basic idea of data processing remains the same, the actual flow of processing, in particular that in the solver module, has changed substantially. As a result, some part of description in Section 3.1 may not be relevant any more.

The Integrated Multi-satelliE Retrievals for GPM (*IMERG*) is the unified U.S. algorithm that provides the multi-satellite precipitation product for the U.S. GPM team.

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.

NASA produces a GIS translation of IMERG for various accumulation periods. The GIS translation maintains the 0.1-degree spatial resolution of the original HDF5 data product. In July 2023, Version 7 IMERG was released in both HDF5 and GIS formats. In April 2019, Version 6 of IMERG had been released, covering June 2000 to 2019. The long- duration archive for all versions starting with Version 6 is a boon to scientific research and provides a training set for near real-time applications such as disaster monitoring.

This document describes the data file formats for all GPM products. Metadata is described in Metadata for GPM Products. The purpose of this file specification document is to define the file content and format for the GPM data products. The file specifications have been reviewed by the algorithm developers. Formats are expected to change for each processing cycle.

Version 7.16 TKIO 3.100

The GPM Combined Radar-Radiometer Algorithm performs two basic functions: first, it provides, in principle, the most accurate, high resolution estimates of surface rainfall rate and precipitation vertical distributions that can be achieved from a spaceborne platform, and it is therefore valuable for applications where information regarding instantaneous storm structure are vital.