Home » Satellite Instruments » TRMM PR
TRMM PR
STATUS
1997 To Current
AVAILABILITY
TRMM Science Data and Information System The real-time processing and post-processing of the TRMM science data is performed by the TRMM Science Data and Information System (TSDIS). Working with the TRMM principal investigators and science algorithm developers, TSDIS maintains the operational science data processing system and ensures the timely processing of all TRMM science instrument data. During routine operations, raw instrument data is received in near real-time by TSDIS and then processed by the first tier of science algorithms to produce calibrated, swath-level instrument data. Using this calibrated, swath-level instrument data, the second tier of algorithms are used to compute geophysical parameters, such as precipitation rate, also at the swath-level resolution. At the final stage of TSDIS processings, the third tier algorithms produce gridded geophysical parameters from the first- and second-tier instrument data. All TRMM products are archived and distributed by the Goddard Distributed Active Archive Center (DAAC). For further information concerning TSDIS operations go to ths TSDIS homepage.
REQUEST PROCEDURE
Distributed Active Archive System The operational archiving and distribution to the public of all TRMM science data products is provided by the Goddard Distributed Active Archive Center (DAAC). In addition to archiving and distributing the TRMM science data, the DAAC also provides necessary information and support for manipulating these data files, which are provided in NCSA's Hierarchical Data Format (HDF). These files are generally distributed on-line. FInally, the DAAC provides front-line support for any questions concerning the TRMM science data. TO obtain TRMM science data, go to the Goddard DAAC homepage. http://daac.gsfc.nasa.gov/data/dataset/HELP/TRMM/FAQ_category_TRMM.shtml http://disc.sci.gsfc.nasa.gov/data/datapool/TRMM/
Satellite Instruments
The Tropical Rainfall Measuring Mission (TRMM) satellite is a joint project between the United States (under the leadership of NASA's Goddard Space Flight Center) and Japan (under the leadership of the National Space Development Agency, or NASDA). The first spacecraft designed to monitor rain over the tropics, was successfully launched from Tanegashima, Japan, on November 27, 1997, at 13:27pm Los Angeles (California) time. TRMM travels between ± 35 degrees latitude in a low earth and low inclination orbit. TRMM is the first mission to measure precipitation quantitatively from space. It includes the first precipitation radar (PR) to be flown in space, along with a 9-channel SSM/I-like passive microwave imager (TMI), an AVHRR-like visible-infrared radiometer (VIRS), a lightning sensor and a cloud sensor. The PR, TMI , and the VIRS are designed to obtain rainfall and other relevant information (e.g. rain type, height of the bright band, cloud type, cloud top height) individually. TRMM is giving scientists a better understanding of what parts of a hurricane produce rainfall and why, as well as possibly resolve the question of how much latent heat or "fuel" hurricanes of differing strengths release into the atmosphere and whether they affect overall weather circulation. The Instrument. The PR actively emits radar pulses toward the ground at frequencies of 13.796 and 13.802 GHz, with horizontal polarization, and measures the strength of the backscatter ("echo" or return signal). Precipitation Radar has a horizontal resolution at the ground of about 2.5 miles (four kilometers) and a swath width of 137 miles (220 kilometers). One of its most important features will be its ability to provide vertical profiles of the rain and snow from the surface up to a height of about 12 miles (20 kilometers). The Precipitation Radar will be able to detect fairly light rain rates down to about .027 inches (0.7 millimeters) per hour. At intense rain rates, where the attenuation effects can be strong, new methods of data processing have been developed that help correct for this effect. The Precipitation Radar is able to separate out rain echoes for vertical sample sizes of about 820 feet (250 meters) when looking straight down. It will carry out all these measurements while using only 224 watts of electric powerÑthe power of just a few household light bulbs. The Precipitation Radar was built by the National Space Development Agency (NASDA) of Japan. The PR measures the echo backscattered from rain: because the strength of the echo is roughly proportional to the square of the volume of falling water, the PR produces very accurate estimates of rain profiles. The PR will determine the vertical distribution of precipitation by measuring the "radar reflectivity" of the cloud systems and the weakening of a signal as it passes through the precipitation . Thus, it will measure the 3-D rainfall distribution over both land and ocean. More specifically, this instrument will define the layer depth of the precipitation and provide information about the rainfall reaching the surface, the key to determining the latent heat input to the atmosphere. TRMM travels between ± 35 degrees latitude in a low earth and low inclination orbit. for low inclination orbit see- http://www.newmediastudio.org/DataDiscovery/Hurr_ED_Center/Satellites_and_Sensors/Low_Inclination_Orbits/Low_Inclination_Orbits.html
CONTACT
Steve Kempler
NASA GSFC DAAC Manager
NASA GSFC DAAC
1-877-422-1222
Steven.J.Kempler@nasa.gov
http://disc.sci.gsfc.nasa.gov/additional/faq/precipitation_faq.shtml
SPECIFICATIONS
Measurment TypeRadar
Platform TypeTRMM PR
OrbitLEO 35 and 'low inclination orbit'
Spectral Coverageuses radar frequencies of 13.796 and 13.802 GHz, with horizontal polarization
Active/PassiveActive
Scan Patternnarrow 220 km swaths 4.3 km resolution at nadir
Variables3D precipitation rainrate
Altitude
Inclination
Repeat Time
Wavelength to
Number of Bands
Temporal Coverage
Swath Width
Resolution 1
Resolution 2
Resolution 3
Resolution 4
REFERENCES
http://tsdis.gsfc.nasa.gov/tsdis/tsdis.html http://tsdis.gsfc.nasa.gov/tsdis/tsdis_redesign/TRMMBackground.html http://www.newmediastudio.org/DataDiscovery/Hurr_ED_Center/Satellites_and_Sensors/TRMM/TRMM.html
REMARKS
http://trmm.gsfc.nasa.gov/publications_dir/breaking_news.html
UPDATED ON
3 Sep 2009 13:47