PPS will Reprocess IMERG Data as IMERG V06B Starting June 05, 2019 Due to an Algorithm Correction

Due to a correction to the GPM IMERG algorithm implemented by the GPM science team, PPS will retract and reprocess all IMERG V06A Final Run GPM and TRMM era data including GIS products as IMERG V06B starting on June 05, 2019.  If you have downloaded IMERG V06A Data previously, please discard this data and use the improved IMERG V06B products as they are produced and archived.

A damaged land/ocean mask file (specifically, a several-gridbox shift to the east and south) was discovered in IMERG V06A,which causes mis-identification of surface type along coasts in theKalman filter computation. While simple to correct, the change in the IMERG results requires shifting to a new sub-version. As of May 22, 2019, the IMERG NRT Early and Late Run files were given the corrected land/ocean mask file and labelled V06B.  The adjustment can be seen in the Early and Late data files starting with June 1, 2019 when the next Kalman statistics were computed.

As was done for V06A, PPS will start the V06B reprocessing with the GPM era, June 2014 - current available data.  This reprocessing will include the GIS products. Once the GPM era is completed, we will start the TRMM-era, June 2000 - May 2014. We will issue necessary update messages as our re-processing effort progresses. The schedule for completing all IMERG V06B processing is not currently known, but will need to reflect balancing the reprocessing with other production computing requirements.

The new V06B TRMM/GPM data products will be made available through PPS's "arthurhou" ftp archive:

and STORM (PPS's Online Data Ordering Interface):
after the products are produced and archived.

NASA requires that all science data users register in order to access these products.  If you haven't registered, please visit the PPS registration portal at:https://registration.pps.eosdis.nasa.gov/registration/

We apologize for any inconvenience this may have caused and thank you for your attention.  Please inform us if you have any questions or concerns.