| The Defense Meteorological Satellite Program (DMSP) satellites collect visible and
infrared cloud imagery as well as monitoring the atmospheric, oceanographic, hydrologic,
cryospheric and near-Earth space environments. The DMSP program maintains a constellation
of sun-synchronous, near-polar orbiting satellites. The orbital period is 101 minutes
and inclination is 99 degrees. The atmospheric and oceanographic sensors record radiances
at visible, infrared and microwave wavelengths. The solar geophysical sensors measure
ionospheric plasma fluxes, densities, temperatures and velocities. DMSP visible and
infrared imagery of clouds covers a 3,000 km swath, thus each satellite provides global
coverage of both day night time conditions each day. The field view of the microwave
imagers and sounders is only 1,500 km thus approximately 3 days data are required
for one instrument to provide global coverage at equatorial latitudes. The solar geophysical
instruments make in-situ measurements of ionospheric parameters, some of which vary
very rapidly. The NOAA National Centers for Environmental Information (formerly National
Geophysical Data Center) receive the complete DMSP data stream from the Air Force
Weather Agency (AFWA), Offutt Air Force Base, Omaha, Nebraska. Data are currently
transmitted in near realtime from AFWA directly to the archive via a designated T1
line. Archive processing prepares orbital data sets of calibrated, quality assessed
data organized as a time-series, restores data lost during transmission,and accurately
computes satellite positions. NCEI maintains an archive of all data recorded on DMSP
satellites as relayed to The NOAA National Centers for Environmental Information (formerly
National Geophysical Data Center) by the Air Force Weather Agency. Data from March
1992 to March 1994, are considered to be experimental. After March 1994, the system
was fully operational. NCEI archives contain data that are post process reconstructed,
positioned and geolocated using the same software. |