Visible/IR imaging multi-spectral radiometers are used to image Earth’s atmosphere and surface, providing accurate spectral information at spatial resolutions of order 100 m up to several km, with a swath width generally in the range several hundred to a few thousand km.

In addition, these observations can be used to study critical components of the water cycle, such as cloud macro- and micro-physical properties, from which information on atmospheric dynamics and pollutants can be determined.

The information obtained from these instruments is often complemented by that from atmospheric sounders, since atmospheric effects such as absorption must be taken into account in deriving parameters such as surface temperatures.

Recent developments include improvements in spatial resolution (which, in some cases, is equivalent to those of high-resolution imagers), spectral resolution, radiometric accuracy and multi-angle capability. Planned hyperspectral instruments that will be able to simultaneously acquire imagery in many tens of wavebands should significantly improve the quality of land cover and land use information derived from satellite imagery.