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.