The Variable Appearance of the Earth from Satellites

The appear:ince of the Earth as seen from space changes continually. These chniigcs it1 bright,iiess and in color are produced by interactioris between (1) geographical factors, such as coasts and mouiitaiiis; (2) scasonal factors, such as t,he brightness c,ii:tnges due t o the deposition and disappearance of siioa’; and (3) mcteorological effects such as the cloud pattcriis indicative of the formation, development, and moveinelit of tropical aiid extratropical disturbances. For example, t o :I satellite, clouds appear as high-energy sources in reflected short-maw, solar eiicrgy, but as cold, lox-energy sources in emitted radiation. A high resolution picturc recovered from the Mercury project is also included. The region of the spectrutii in which the Earth is viewed infiueiices it,s appearance. All these effects are illustrated with pictures and measureinciits from TIROS satellites.