Defense Meteorological Satellite Program (DMSP)

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 National Geophysical Data Center (NGDC) receives 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 NGDC via a designated T1 line. NGDC 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. NGDC maintains an archive of all data recorded on DMSP satellites as relayed to NGDC 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. NGDC archives contain data that are post process reconstructed, positioned and geolocated using the same software.