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Integrated Multi-satellitE Retrievals for GPM (IMERG) Data Released through NASA GES DISC

Data release continues heritage of TRMM with refined and improved precipitation data

Integrated Multi-satellitE Retrievals for GPM (IMERG) Data Released through NASA GES DISC

IMERG data from the GPM mission provide accurate global satellite observations of rain and snow.

Integrated Multi-satellitE Retrievals for GPM (IMERG) Data Released through NASA GES DISC

 The Goddard Earth Sciences Data and Information Services Center (GES DISC), in coordination with the Global Precipitation Measurement (GPM) mission and the Precipitation Processing System (PPS), announces the release of the Integrated Multi-satellitE Retrievals for GPM (IMERG) data.

Launched on February 27, 2014, the GPM mission comprises an international network of satellites that are providing the next generation of global observations of rain and snow. Built upon the success of the widely-used TRMM Multi-satellite Precipitation Analysis (TMPA) products, the IMERG products continue to provide improvements in many areas such as spatial and temporal resolutions, snowfall estimates, etc., which will be valuable for research and applications.

Generation of these data products requires the integration of data from precipitation gauges, which helps to control biases that can occur in satellite precipitation data.  Once the monthly gauge analysis is received, the “Final” satellite-gauge product will become available, approximately 2 months after the month in which the observations were made.

The "Final" satellite-gauge product is available in the current release, consisting of half-hourly and monthly datasets beginning on March 12, 2014. The "Early" and "Late" products will be released in late 2015.

Tables 1 and 2 list data fields, their variable names (in the data structure), and the data units for half-hourly (3IMERGHH) and monthly (3IMERGM) data files, respectively. Figure 1 is a map of the calibrated precipitation at 03Z on June 15, 2014, showing flooding rain rates in the midwestern United States (see http://trmm.gsfc.nasa.gov/publications_dir/iowa_rain_2014.html for details). Figure 2 is the June monthly accumulated rainfall derived from the monthly file (3B-MO.MS.MRG.3IMERG.20140601-S000000-E235959.06.V03D.HDF5), showing the heavy rainfall event in the Midwestern region.

 

Table 1. List of data fields, their variable names, and the data units for half-hourly (3IMERGHH) data files (from: http://pmm.nasa.gov/sites/default/files/document_files/IMERG_doc.pdf). 

 

Data field
Variable name
Units
snapshot precipitation – calibrated
 
precipitationCal
mm/hr
snapshot precipitation – uncalibrated
 
precipitationUncal
mm/hr
calibrated-precipitation random error
 
randomError
mm/hr
merged PMW precipitation
 
HQprecipitation
mm/hr
PMW source sensor identifier
 
HQprecipSource
index values
PMW source time
 
HQobservationTime
min. into half hour
IR precipitation
 
IRprecipitation
mm/hr
Kalman filter weight for IR
 
IRkalmanFilterWeight
percent
probability of liquid precipitation phase
 
probabilityLiquidPrecipitation
percent

 

Table 2.  List of data fields, their variable names (in the data structure), and the data units for monthly (3IMERGM) data files (from: http://pmm.nasa.gov/sites/default/files/document_files/IMERG_doc.pdf).

 

Data field
Variable name
Units
satellite-gauge precipitation
 
precipitation
mm/hr
satellite-precipitation random error
 
randomError
mm/hr
gauge relative weighting
 
gaugeRelativeWeight
percent
accumulation-weighted probability of liquid precipitation phase
 
 
probabilityLiquidPrecipitation
percent

 

The calibrated precipitation in mm/hr (3B-HHR.MS.MRG.3IMERG.20140615-S030000-E032959.0180.V03D.HDF5) at 03Z June 15, 2014 in the Midwestern United States.

Figure 1. The calibrated precipitation in mm/hr (3B-HHR.MS.MRG.3IMERG.20140615-S030000-E032959.0180.V03D.HDF5) at 03Z June 15, 2014 in the midwestern United States.  Click for full-size. 
 
 
Monthly accumulated rainfall in mm (derived from 3B-MO.MS.MRG.3IMERG.20140601-S000000-E235959.06.V03D.HDF5), showing the heavy rainfall in the midwestern United States.
 
 
Figure 2.  Monthly accumulated rainfall in mm (derived from 3B-MO.MS.MRG.3IMERG.20140601-S000000-E235959.06.V03D.HDF5) for June 2014, showing the heavy rainfall in the midwestern United States.  Click for full-size.
 

Data Access

Users can access these data products through the Data Holdings Web interfaces for IMERG half-hourly and monthly  products, which provide access to the data, documentation, and services for each product. You can also directly access the products through the following methods: 

 

Additional Tools and Services:

 
 

Key documents:

 
Release document:
 
ReadMe Document for GPM Data 
 

Questions or comments? Email the NASA GES DISC Help Desk: gsfc-help-disc@lists.nasa.gov



 

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Last updated: Feb 23, 2015 05:58 PM ET
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