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TRMM TMI
STATUS
Current But Beyond Lifetime
AVAILABILITY
http://daac.gsfc.nasa.gov/data/dataset/HELP/TRMM/FAQ_category_TRMM.shtml
REQUEST PROCEDURE
http://daac.gsfc.nasa.gov/data/dataset/HELP/TRMM/FAQ_category_TRMM.shtml
Satellite Instruments
The Tropical Rainfall Measuring Mission's (TRMM) Microwave Imager (TMI) is a passive microwave sensor designed to provide quantitative rainfall information over a wide swath under the TRMM satellite. By carefully measuring the minute amounts of microwave energy emitted by the Earth and its atmosphere, TMI is able to quantify the water vapor, the cloud water, and the rainfall intensity in the atmosphere. It is a relatively small instrument that consumes little power. This, combined with the wide swath and the good, quantitative information regarding rainfall make TMI the "workhorse" of the rain-measuring package on Tropical Rainfall Measuring Mission. TMI is not a new instrument. It is based on the design of the highly successful Special Sensor Microwave/Imager (SSM/I) which has been flying continuously on Defense Meteorological Satellites since 1987. The TMI measures the intensity of radiation at five separate frequencies: 10.7, 19.4, 21.3, 37, 85.5 GHz. These frequencies are similar to those of the SSM/I, except that TMI has the additional 10.7 GHz channel designed to provide a more-linear response for the high rainfall rates common in tropical rainfall. The other main improvement that is expected from TMI is due to the improved ground resolution. This improvement, however, is not the result of any instrument improvements, but rather a function of the lower altitude of TRMM 250 miles (402 kilometers) compared to 537 miles (860 kilometers) of SSM/I). TMI has a 547 mile (878-kilometer) wide swath on the surface. The higher resolution of TMI on TRMM, as well as the additional 10.7 GHz frequency, makes TMI a better instrument than its predecessors. The additional information supplied by the Precipitation Radar further helps to improve algorithms. The improved rainfall products over a wide swath will serve both TRMM as well as the continuing measurements being made by the SSM/I and radiometers flying on the NASA's EOS-PM and the Japanese ADEOS-II satellites. TRMM is NASA's first mission dedicated to observing and understanding the tropical rainfall and how this rainfall affects the global climate. It is a joint mission with the National Space Development Agency of Japan. The primary instruments for measuring pre-cipitation are the Precipitation Radar, the TMI, and the Visible and Infrared Scanner. Additionally, TRMM carries the Lightning Imaging Sensor and the Clouds and the Earth's Radiant Energy System Instrument. These instruments can all function individually or in combination with one another. TRMM is part of NASA's Mission to Planet Earth, a long-term, coordinated research effort to study the Earth as a global system.
CONTACT
Steve Kempler
NASA GSFC DAAC Manager
Goddard Earth Sciences Data and Information Services Center NASA Goddard Space Flight Center Code 610.2 Greenbelt, MD 20771 USA
301-614-5224
Steven.J.Kempler@nasa.gov
http://disc.sci.gsfc.nasa.gov/additional/faq/precipitation_faq.shtml
SPECIFICATIONS
Measurment TypeMicrowave imager
Platform TypeTRMM TMI
OrbitLEO 35 and 'low inclination orbit'
Spectral CoverageMicrowave 10.7, 19.4, 21.3, 37, 85.5 GHz
Active/PassivePassive
Scan Patternconical scan
Variablesprecipitation, sea ice, wind speed, total column water liquid/vapor
Altitude
Inclination
Repeat Time
Wavelength to
Number of Bands
Temporal Coverage
Swath Width
Resolution 1
Resolution 2
Resolution 3
Resolution 4
REFERENCES
http://trmm.gsfc.nasa.gov/overview_dir/tmi.html
REMARKS
http://trmm.gsfc.nasa.gov/data_dir/data.html
UPDATED ON
3 Sep 2009 13:47