Abstract

During the past two decades, passive infrared and microwave radiometers have been used to provide vertical temperature and moisture profiles from meteorological satellites. The infrared instruments have evolved from the medium spectral and low spatial resolution interferometer and grating spectrometer flown on the Nimbus III satellite in 1969 to the high spatial and low spectral resolution filter radiometers currently flying on the operational polar orbiting (NOAA) and geostationary (GOES) satellites. The microwave radiometers utilized have been of the conventional Dicke design. The evolution of the infrared sounding instruments has been driven by the need for high spatial resolution to probe the clear air interstices of the earth's broken cloud cover. Microwave sounders, which penetrate clouds, were initially much larger and heavier and consumed more power than infrared radiometers when compared to infrared sounders on a per channel per unit field-of-view basis. Advances in microwave radiometer technology have permitted the number of spectral channels to be increased, the field-of-view reduced, and the signal-to-noise ratio to be improved without a corresponding increase in the weight, volume, and power requirements.

© 1983 Optical Society of America