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. 

PPS has completed the retrospective processing of IMERG NRT early and late products to version V06B. All GPM NRT IMERG is available at version V06B from June 2014 through the current IMERG data. The GPM NRT IMERG from March 2014 through May 2014 will be available once the TRMM era (2000-2014) retrospective processing is completed. THe V06B data is the default product (early and late) available on the jsimpson.pps.eosdis.nasa.gov NRT file server. Please contact us for any questions.
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. IMERG early and late are being produced again at their required latency: a. early: approx 4 hours from data collection b. late: approx 14 hours from data collection We are sorry for the extended unavailability of the 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.
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...
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.

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