NOAA remote sensing missions and frequency issues

The National Environmental Satellite, Data, and Information Service (NESDIS) in the National Oceanic and Atmospheric Administration (NOAA) oversees two operational satellite systems, viz., the NOAA polar-orbiting environmental spacecraft (POES) and Geostationary Operational Environmental Satellites (GOES). The GOES satellites, located above the equator at 75° and 135° west longitude, provide continuous imagery of Western Hemispheric weather conditions by monitoring cloud motions and development as detected by visible and infrared sensors. Similar sensors on the two NOAA satellites provide worldwide observations once a day in the visible and twice a day in the thermal infrared. All-weather microwave instruments on the polar-orbiters also profile atmospheric temperature and moisture. Such data are highly perishable if not available as input to numerical weather prediction models within 3 hours after acquisition. The use of microwave frequencies to transmit signals from Earth to space and from space to Earth is a necessary component of each satellite system. Additionally, the detection of a portion of the naturally occurring radiation from the Earth´s atmosphere by satellite passive sensors also falls in the microwave portion of the electromagnetic spectrum. Transmission of these vital data to Earth and commands from Earth to the spacecraft to maintain spacecraft integrity depend on specific radio frequencies allocated for meteorological satellite use by the International Telecommunication Union (ITU). The frequencies used by the NOAA POES and GOES satellites, respectively, are given