Spaceborne microwave radiometers: Background and technology requirements

Spaceborne microwave radiometer requirements in atmospheric, oceanographic, and cryospheric applications are discussed. Data processing is considered. Although still in a development phase, microwave radiometry shows examples of operational applications in the fields of atmospheric sounding and sea ice monitoring. The 10-channel Scanning Multichannel Microwave Radiometer on SEASAT and NIMBUS-7 is shown to have a good concept. However, experience suggests that improvements of the techniques, the calibration method, and the data retrieval are desirable. Developments over the past decade concern frequencies below 60 GHz and antenna and receiver techniques as well as development of suitable data retrieval methods.