IMERG V07 Release Notes

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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).

Retrospective Processing (RP) for the Final Run began on 1 July 2023 and completed on 30 August 2023. However, discovery of some 162 orbits of defective V07 GPROF precipitation estimates across all passive microwave satellites over the TRMM and GPM eras led to a second RP for the V07 Final Run, now labeled V07B. The relatively long pause between the first Final Run RP and this second is partly due to an orbit boost that the GPM Core Observatory (GPM-CO) satellite performed on 7-8 November 2023. The second RP for the entire TRMM-GPM record was completed on 8 January 2024. Subsequently, the IMERG team examined changes caused by the orbit boost on the Combined Radar-Radiometer Algorithm (CORRA) and the Precipitation Processing System (PPS) undertook a mandatory switch in operating systems. Following these actions, climatological calibrations were computed for the Early and Late Runs to the Final Run, and both Initial Processing (IP) and RP for the Early and Late Runs began on 3 June 2024, with IP taking effect starting 1 June. A gap existed between the RP and IP for Early and Late until the Final was completed for May 2024, since these RPs depend on various intermediate files computed in Final. Links to the IMERG files are listed on the Data Directory of the GPM website: https://gpm.nasa.gov/data/directory, which point to archives hosted at the Goddard Earth Sciences Data and Information Services Center (GES DISC) https://disc.gsfc.nasa.gov/datasets?keywords=gpm%20imerg%2007 and PPS https://arthurhou.pps.eosdis.nasa.gov/Documents/Master_List_of_PPS_Data…, as well as several interactive sites. Please visit https://gpm.nasa.gov/data/news for the latest updates.

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IMERG_V07_ReleaseNotes_241126.pdf
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