The Tropical Rainfall Measuring Mission (TRMM) is a joint U.S.-Japan
satellite mission to monitor tropical and subtropical precipitation
and to estimate its associated latent heating. TRMM was successfully
launched on November 27, at 4:27 PM (EST) from the Tanegashima Space ... Center in Japan.
The Visible and Infrared Scanner (VIRS) is a five-channel
visible/infrared radiometer, which builds on the heritage of the
Advanced Very High Resolution Radiometer (AVHRR) instrument flown
aboard the NOAA series of Polar-Orbiting Operational Environmental
Satellites (POES). The VIRS detects radiation at 1 visible, 2 near
infrared and 2 thermal infrared wavelengths, allowing determination of
cloud coverage, cloud top height and temperature, and precipitation
indices. The central wavelengths for the VIRS channels are 0.63, 1.60,
3.75, 10.8, and 12.0 microns. All channels are in operation during the
daytime, but only channels 3, 4 and 5 operate during the nighttime.
The Level 1A product file (1A01) is a concatenation of the Level 0
data with a header record and, as such, is reversible to Level 0. The
header record contains information pertaining to orbit times, orbit
number, times of the first scan, and number of scans, among other
things. The Level 0 data contain the actual channel data expressed as
"sensor counts". A Level 1A file contains data for a single orbit and
has a file size of about 31 MB (uncompressed). There are 16 files
of VIRS 1A01 data produced per day.
Spatial coverage is between 38 degrees North and 38 degrees South
owing to the 35 degree inclination of the TRMM satellite. This orbit
provides extensive coverage in the tropics and allows each location to
be covered at a different local time each day, enabling the analysis
of the diurnal cycle of precipitation.