IR sounder technology trends

Advanced IR sounding benefits partly from cloud-top parameter and surface emissivity estimates, using coincident imaging spectroradiometry. While a separate imager on the same spacecraft on which the sounder is located can provide closely coincident surface and cloud parameter estimates, an "imaging sounder" that can deliver image and sounding data may reduce cost. Key technology trends enabling low-risk "imaging sounders" include better and lower cost optics, improved spectral-separation, low-noise wide bandwidth large area focal plane arrays, reliable active cooling, and low-power, higher density electronics for high-rate analog-to-digital conversion and on-board data processing. Trends over the last decade and efforts underway are identified with improvements anticipated in the next decade. Applications are described with reference to instrumentation either in-orbit or under development.