PRECIPITATION MEASUREMENT MISSIONS

There are several sources where the TRMM rainfall data can be accessed:

Quicklooks and Data Visualization

• Quicklooks: Provides an image of the most recent daily TRMM Microwaver Imager (TMI) measurements as a global map.
• TRMM Products: A range of different TRMM products are provided through the TRMM portal, including rainfall accumulations, climatologies and anomalies.
• TRMM Online Visualization and Analysis Systems (TOVAS): Web-based interface for the visualization and analysis of TRMM data through the Giovanni (GES-DISC DAAC Online visualization and Analysis System).
• Google Earth: Provides TRMM precipitation data visualizations as .KML overlays for Google Earth, so they can be viewed on an interactive 3D globe.

Downloading Data

• Anonymous FTP: The TRMM data is available online through an anonymous FTP site. Click the link to see a description of the subdirectories for these products.
• Interactive Data Downloading and Subsetting (Mirador): The Goddard Earth Sciences (GES) Data and Information Services Center (DISC) Distributed Active Archive Center (DAAC) provides operational archiving and distribution to the public of all TRMM science data products. Mirador offers a straightforward way to subset selected TRMM products in both space and time and convert to several data formats.
• STORM - Science Team On-Line Request Module (TRMM Data Ordering): TRMM products are also available to users via STORM, where data can be obtained via geographical subsets.
• Ground Validation Data: Data from the various PMM ground validation missions and field campaigns can be accessed through a variety of sources.

Quicklooks

Provides an overview of daily TMI swatch data. Each quick-look is generated at a resolution of 1/4 degree, thus generating an image of 1440x720 pixels, or a file size of about 500k.
 

TRMM Products

The TRMM webpage provides a range of different TRMM products. The rainfall accumulation products are updated in every 3-hours and provide both 3 and 7-day accumulation maps from 50°N to 50°S. Other products include a TRMM Climatology, Rainfall Anomalies, and monthly accumulation maps.
 

TRMM Online Visualization and Analysis System (TOVAS)

TOVAS is a member of the Giovanni (GES-DISC DAAC On-line Visualization and Analysis System) family, which provides users with an easy-to-use, Web-based interface for the visualization and analysis of Earth Science data. Many TRMM products are available for analysis and data can be plotted in both space and time to provide a range of outputs. The TOVAS system is currently undergoing an upgrade. Several new functions and parameters have been added along with additional data download formats (HDF, NetCDF and KMZ). As planned, all current TOVAS instances, listed below in this page, will be similarly converted to the new system.
 

Google Earth

TRMM provides precipitation visualizations in .KML format for use with the free Google Earth software (download here). Products provided in this format include 30 day rainfall averages and anomalies, hourly rainfall accumulation, and hourly flood potentials.

Anonymous FTP Data Downloads

Merged Data

A series of quasi-global, near-real-time, TRMM-based precipitation estimates is available to the research community via anonymous ftp. Information for this directory can be found here. The estimates are provided on a global 0.25° x 0.25° grid over the latitude band 50° N-S within about seven hours of observation time. Three products are being provided:

1. A TRMM-calibrated merger of all available TMI, AMSR-E, SSM/I, and AMSU-B precipitation estimates (three-hourly accumulations).
2. A geosynchronous infrared estimate which is calibrated by the merged-microwave data (hourly estimates).
3. A combination of the first two fields (three-hourly accumulations).

The data are available under ftp://trmmopen.gsfc.nasa.gov/pub/merged. Users are urged to download the README first for additional details. This site currently provides Version 6 (V06) products. Once Version 7 begins, the site will host Version 6 up to when Version 7 (V07) starts, at which point V07 will be the primary version.

All Data Products

There are also a series of products available at ftp://trmmopen.gsfc.nasa.gov/pub/trmmdata. The directories contain a wide variety of products described above. Please refer to the PPS Documentation before continuing to the FTP site, which describes naming conventions, product descriptions, and examples of how to read TRMM data products. The Documentation site also provides sample programs and tutorials for how to read in TRMM product data. Below we briefly describe the type of data provided within each directory:

• 3G: Provides gridded text data in daily files. Directories include:
  3G01-4: Channel 4 VIRS
  3G01-5: Channel 5 VIRS
  3G68: 0.5 x 0.5 degrees
  3G68Land: Australia, South America, Africa at 0.1 x 0.1 degrees
  3G68-Q: 0.25 x 0.25 degrees
• ByDate: Full HDF Files for each product arranged by date.
• ByInstrument: Full HDF Files for each product, arranged by date.
• GIS: PPS has developed prototype files of TRMM’s 3B42 Product in TIF files, which is compatible with Geographic Information Systems (GIS). Data are arranged as 50°N-S time slices for each year, month, and day. More information on GIS Prototypes from PPS is available here. All products may also be obtained through STORM.

For information about Precipitation Feature (PF) products, please visit the University of Utah website.
 

Mirador

The operational archiving and distribution to the public of all TRMM science data products is provided by the GES DISC DAAC. In addition to archiving and distributing the TRMM science data, the GES DISC DAAC also provides necessary information and support for manipulating these data files, which are provided in NCSA's Hierarchical Data Format (HDF) and NetCDF. All files are distributed on-line. The GES DISC DAAC provides front-line support for any questions concerning the TRMM science data. TRMM and other precipitation data and services are provided through PDISC, part of the GES DISC DAAC.
 

STORM

Science Team On-Line Request Module (TRMM Data Ordering) (STORM) provides an additional way to query, research, and download TRMM products. This site also provides related links to TRMM content, PPS activities, and additional product information.
 

Ground Validation Data

Access to LPVEx data

A significant portion of the LPVEx dataset is now available for access via the GPM GV data archive at the GHRC DAAC, and by SFTP at the CloudSat GV data archive at CSU CIRA. A formal announcement for release of the complete dataset will occur no later than December 2011. Contact Walt Petersen for more information.

Access to C3VP data

A summary table and information on how to access C3VP data is available.

Data products from many investigators are available without restriction and can be accessed via the ftp sites identified in the table. Points-of-contact listed on the table can be consulted for more information on the data format and content, and on other details of data access and use.

Access to Validation Network Data, Software, and Documentation

Please direct your inquiry for Validation Network data to the GPM GV contacts. The software that runs the Validation Network is now open source, and is available at the Goddard Open Source page. The Validation Network Data User's Guide provides detailed descriptions of the VN data format and contents.

Access to Radar Profiler and Related Data

Radar profiler data were collected by Dr. Christopher Williams from the University of Colorado at Boulder/NOAA Earth System Research Laboratory under funding from NASA's Precipitation Measurement Mission. The data are being provided to the NASA PMM community to help validate and improve satellite retrieval algorithms and cloud resolving models. The data sets are derived from surface rain gauges, a disdrometer and vertical pointing profilers deployed at the Australian Bureau of Meteorology Research Centre (BMRC) wind profiler site near Darwin, Australia during the Tropical Western Pacific - International Cloud Experiment (TWP-ICE). Documentation to the data can be found by clicking here.