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. 

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. Final Run retrospective processing for V06B will...
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. +-------+----------------+---------------------+-------+ | AlgId | ProductVersion | StopTime | SeqNo | +-------+----------------+--------------...
On 1 May 2019, at approximately 14 UTC, PPS will stop production of IMERG V05 in order to setup and install the new IMERG V06 code for production of early and late products. This will require an extended period when no IMERG products will be produced or available for users. We estimate an extended period of IMERG unavailability that may last for 5 hours or more. Upon resumption of IMERG production, V06 will start with data from 1 May 2019 hour 00 UTC. We will reestablish latency of early products to 4 hours, and late products to 14 hours, as soon as possible. We will also start V06 retro-processing of IMERG early and late products back to the beginning of the GPM mission. These will be available on the server as they are produced.
An error has been discovered in processing the initial batches of V06 IMERG Final Run months. A design choice in the code ended up retaining microwave precipitation estimates in the latitude band 60°N-S when there is snow/ice on the surface, rather than masking out the estimates due to low performance in such cases. [Masking for microwave retrievals over surface snow and ice outside that band is correct.] All V06A Monthly and Half-hourly IMERG products are being retracted, as shown in this table (Encompassing all IMERG V06A data that had been reprocessed and archived -to date): ----------+----...
Starting this week (Wednesday March 13, 2019 or soon after) PPS will commence GPM IMERG data reprocessing for IMERG V06. PPS will start reprocessing with the GPM-era data and will make these products available as they are archived. Thereafter, we will reprocess the TRMM-era data. The first available products for the GPM-era will start with June 2014. TRMM-era products will span June 2000 - May 2014. Earlier TRMM-era processing, 1998-01 to 2000-05, will proceed when all required input data have been provided. We have attached the latest IMERG documentation for your convenience. Developers and...

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