TRMM Microwave Imager (TMI) Rainfall Products
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Sensor Description:
- The TMI is a nine-channel passive microwave radiometer based upon
the Special Sensor Microwave/Imager (SSM/I). The key differences
are the addition of a pair of 10.7-GHz channels with horizontal
and vertic al polarizations and a frequency change of the water
vapor channel from 22.235 to 21.3 GHz. This change off the center
of the water vapor line was made in order to avoid saturation in the
tropical orbit of TRMM. In addition, the TMI has significantly
higher spatial resolution than SSM/I due to the lower orbit of the
TRMM satellite.
Algorithm Description:
- GPROF 2008: The rainfall algorithm used to compute rainfall estimates from the TMI brightness temperature data is the 2008 release of the Goddard PROFiling algorithm (GPROF) [Kummerow et al., 2001, Masunaga and Kummerow, 2005]. The TMI version of GPROF is run operationally by the Precipitation Processing System (PPS) and is referred to as the 2A12 algorithm. The current plan is for the PPS to begin processing GPROF 2008, which will be called 2A12 version 7, once the algorithm is finalized in late 2010. Additional information is available on the TMI implementation details.
- Version Information:
- GPR08.B2 (GPROF 2008 beta version 2): B2 is a beta version 2, indicating that the rainfall estimates from this beta version are still preliminary.
- GPR08.B3 (GPROF 2008 beta version 3): B3 is a beta version 3. Minor changes were made to the level 2 output, however, the gridded data files are unchanged from version B2.
- GPR08.B4 (GPROF 2008 beta version 4): B4 is a beta version 4. A number of changes were made to the level 2 output including the addition of a data quality flag. There are significant changes in the output data fields particularly with respect to rainfall estimates over land and coast.
Input Brightness Temperature Data:
- The rainfall products provided here are computed from the Level 1C brightness temperature dataset.
Data Availability:
- The TRMM satellite was launched on November 27, 1997 with rainfall estimates available from December 8, 1997 through to the present. Because the inclination of TRMM is only 35 degrees the rainfall estimates from TMI are limited to the tropics, extending from approximately 38S to 38N.
Rainfall Data:
- FTP Daily and Monthly Gridded Rainfall Data Files
- File Format Specification for Daily Gridded Rainfall Files
- File Format Specification for Monthly Gridded Rainfall Files
Rainfall Images:
- Create/Display Daily Rainfall Images
- Create/Display Monthly Rainfall Images
- FTP Pre-rendered Rainfall Images
Software:
- Get software to read the binary gridded rainfall files.
Additional Documentation/References:
– Kummerow, C., W. Barnes, T. Kozu, J. Shiue, and J. Simpson, 1998: The Tropical Rainfall Measuring Mission (TRMM) sensor package, J. Atmos. Oceanic Technol., 15, 809-817. – Kummerow, C. and Coauthors, 2000: The status of the Tropical Rainfall Measuring Mission (TRMM) after two years in orbit, J. Appl. Meteor., 39, 1965-1982. – Kummerow, C., Y. Hong, W. S. Olson, S. Yang, R. F. Adler, J. McCollum, R. Ferraro, G. Petty, D. B. Shin, and T. T. Wilheit, 2001: The evolution of the Goddard profiling algorithm (GPROF) for rainfall estimation from passive microwave sensors, J. Appl. Meteor., 40, 1801-1820. – Masunaga, H. and C. D. Kummerow, 2005: Combined radar and radiometer analysis of precipitation profiles for a parametric retrieval algorithm, J. Atmos. Oceanic Technol., 22, 909-929. Related Links:
- Goddard Data and Information Services Center (DISC)
- NASA TRMM Home Page
- JAXA TRMM Home Page