IMERG Early Run Example January 24th, 2020

Data

Precipitation data from the GPM and TRMM missions are made available free to the public in a variety of formats from several sources at NASA Goddard Space Flight Center. This section outlines the different types of data available, the levels of processing, the sources to download the data, and some helpful tips for utilizing precipitation data in your research.

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Frequently Asked Questions

How do I get precipitation data for my specific location?

There are several sources for downloading and viewing data which allow you to subset the data to only include specific parameters and/or geographic locations. These include the GES DISCGiovanni and STORM. In Giovanni you can obtain data for a specific country, U.S. state, or watershed by using the "Show Shapes" option in the "Select Region" pane.

What happened to the TRMM Multi-satellite Precipitation Analysis (TMPA / 3B4x) data products?

The TRMM satellilte has been decommissioned and stopped collecting data in April 2015. The transition from the Tropical Rainfall Measuring Mission (TRMM) data products to the Global Precipitation Measurement (GPM) mission products has completed as of August 2019. The GPM IMERG dataset now includes TRMM-era data from June 2000 to the present, and other TRMM-era data has been reprocessed with GPM-era algorithms and is now available on the GPM FTP servers. TMPA data production ended as of December 31st, 2019 and the TRMMOpen FTP server has been shut down. Historical TMPA data is still available to download from the NASA GES DISC at: https://disc.gsfc.nasa.gov/datasets?keywords=TMPA&page=1

Click here for more details on the transition from TMPA to IMERG. 

Am I allowed to use GPM data for my research?

Yes, in line with NASA's general data policy. Please refer to the GPM Data Policy for further details.

How do I give credit for using GPM data?
Where can I find detailed documentation on the precipitation algorithms?

Browse our directory of GPM & TRMM data products to locate your desired algorithm, then click on the links in the algorithm description under "Documentation". All documentation is also available at the Precipitation Processing System website

What is the spatial and temporal resolution of GPM data?

The resolution of Level 0, 1, and 2 data is determined by the footprint size and observation interval of the sensors involved.  Level 3 products are given a grid spacing that is driven by the typical footprint size of the input data sets.

For our popular multi-satellite GPM IMERG data products, the spatial resolution is 0.1° x 0.1° (or roughly 10km x 10km) with a 30 minute temporal resolution.

Visit the directory of GPM & TRMM data products for details on the resolution of each specific products.

Can I use images or videos from this site or other NASA websites?

For questions about permission for using NASA images and videos, please refer to NASA's official Media Usage Guidelines. For any additional questions please contact bert.ulrich@nasa.gov

Is it possible to subset GPM data?

There are several sources for downloading and viewing data which allow you to subset the data to only include specific parameters and/or geographic locations. These include the GES DISCGiovanni and STORM. In Giovanni you can obtain data for a specific country, U.S. state, or watershed by using the "Show Shapes" option in the "Select Region" pane.

What is the difference between "Near Real-time" (NRT) and "Production" / "Research" data?

GPM data products can be divided into two groups (near real-time and production) depending on how soon they are created after the satellite collects the observations. For applications such as weather, flood, and crop forecasting that need precipitation estimates as soon as possible, near real-time data products are most appropriate.  GPM near real-time (GMI & DPR) products are generally available within a few hours of observation.  For all other applications, production data products are generally the best data sets to use because additional or improved inputs are used to increase accuracy.  These other inputs are only made available several days, or in some cases, several months, after the satellite observations are taken, and the production data sets are computed after all data have arrived, making possible a more careful analysis.

For the GPM IMERG dataset, IMERG Early and Late Runs are the near real-time products, while IMERG Final Run is the research / production product. Click here to learn more about the differences between IMERG Early, Late and Final. 

Beginning on April 6, anomalies in the input SSMIS F17 precipitation estimates were detected in the IMERG Early and Late runs. These anomalies manifest as episodic “swath shaped” areas of high precipitation over land which appear to affect most orbits to some degree. The root cause is degradation in the 37 GHz V polarization channel. On April 13 the issue was somewhat mitigated but we continue to monitor the situation. Please let us know if you detect these (or other anomalies) in the IMERG Early and Late Runs after April 13.
Late on March 2, 2016, the GPM NRT system will begin using V04 algorithms for: Level 1B GMI Level 1C GMI Level 1 Radar Level 2 Radar Level 2 Combined V04 is the first version that uses GPM as the calibrator for the constellation rather than TRMM. The GPROF database is built using the combined observations. GMI is extremely well calibrated and the brightness temperatures in 1B and 1C are an important improvement over those in V03. V04 also made improved retrievals in the Ku, Ka, and DPR Level 2 products. Combined has also made retrieval improvements in this version. GPROF the algorithm used for...
PPS will commence Version 4 processing of GPM and Partner satellite products in early March 2016. All current Version 3 products will be processed through February 29, 2016. Once the current products are completed there will be a delay before the first version 4 products will be made available to the public. The first data date for version 4 will be March 1, 2016. Once PPS has verified the processing and products for version 4 they will be released and made available from our ftp site. At this time PPS will commence reprocessing. GPM products will be reprocessed back to launch, March 2014...
UPDATE 2/22/16: The network upgrades have finished and normal service has been restored. Due to scheduled external GSFC network upgrades, PPS will experience intermittent and unpredictable network outages during the period of Friday February 19, 2016 (starting 8:00PM EST-0100 UTC) through Monday February 22, 2016 (3:00 AM EST-0800 UTC). This work will impact access to the following PPS services: PPS ftp production data (arthurhou) PPS ftp NRT data-Near Realtime (jsimpson) PPS Public website: http://pps.gsfc.nasa.gov/ STORM: https://storm.pps.eosdis.nasa.gov/ PMM website: http://pmm.nasa.gov...
The Washington, DC area is about to get hit with a record-level snow storm, with attendant disruptions to work schedules, travel, communications, and power. If you find that the TMPA-RT products drop out, it is safe to assume that some combination of these effects is preventing production, and we will work to restore service when that is possible.

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