GPM

Content which is affiliated solely with the Global Precipitation Measurement Mission.

IMERG Processing and Availability

On 16 June 2019 at 22 UTC several hours of missing IR data and subsequent handling of this outage caused IMERG early and late products to be produced without IR data since that date/time.  To ensure consistent early and late IMERG products it was decided to retroprocess these IMERG early and late products.

All early and late IMERG products from 16 June 2019 at 22:00 UTC through June 19 were retroprocessed. You may wish to download the revised products from 16 June 2019 22:00 UTC  onword.

Measuring Latent Heating in Storm Systems

How TRMM and GPM Study Latent Heating

Latent heating (LH) arises predominantly from the release of heat associated with the condensation of water vapor into cloud droplets in clouds with active updrafts.  Other sources of LH include ice deposition and freezing, while evaporation, melting and sublimation induce cooling, but condensation is the dominant heating term.  Like a hot-air balloon, LH can keep air parcels warmer than their surrounding environment and therefore rising.  On a large scale, LH is responsible for driving the ascending branch of the Hadley Circulation.

Interruption of NOAA Products

Effective around 12:00 UTC 10 June the MHS and ATMS input to real-time IMERG suddenly became unavailable due to an unexpected change in NOAA protocols.  While PPS scrambles to remedy the issue, the data content of the Early and Late Runs may be reduced for the next several days, meaning lower Quality Index due to longer morphing of microwave estimates and greater contributions by IR.

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.

Retraction of IMERG Final V06A and V06B Processing

All IMERG V06A Final products will be retracted later today.  

On Wednesday, June 5, PPS will start the V06B reprocessing beginning with the GPM era, June 2014 - current available data.  Once the GPM era is completed, PPS will start the TRMM-era, June 2000 - May 2014.

Due to capacity loads at PPS, there are no firm estimates as to how long this will take. 

V06A is being retracted due to a corrupt surface coverage file in the Kalman statistics computation.  

Please contact us for any questions.

Using GPM Data to Understand Hurricanes

Using GPM Data to Understand Hurricanes

The 2019 Atlantic "hurricane season" is officially upon us and runs through November 30th. Did you know that GPM data play a fundamental role in the ability to monitor existing storm activity such as capturing the location and intensity of rainfall inside a storm, as well as improving weather and precipitation forecasts through assimilation of instantaneous precipitation information? Here are a few applications of GPM data used to study hurricanes and how the data was then used for decision-making.

Change in Early and Late IMERG Product Version

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

PPS Announcing GPM 1AGM Version Update from V05A to V05B

PPS will be updating GPM 1AGMI data from V05A to V05B today, Thursday May 09, 2019 because there was a minor bug in the algorithm.  Only 1AGMI will change versions.

The L1AGMI executable was previously not filling in a missing scan if there was an error in reading or processing the scan data from the instrument.  Nothing was being generated in the GMI 1A product in this case.  The bug fix was to fill in a missing scan and annotate this in the file header.

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