Remote Sensing of Terrestrial Clouds from Space using Backscattering and Thermal Emission Techniques

Clouds play an important role in terrestrial atmospheric dynamics, thermodynamics,chemistry, and radiative transfer and are key elements of the water and energycycles. Cloud properties can be modified by anthropogenic and natural gaseous andaerosol emissions (i.e. aerosol indirect effect) and are important for understandingclimate change. Therefore, it is of a great importance to understand cloud char-acteristics and their distributions on a global scale. This can only be achieved usingsatellite observations.The first picture of cloud fields from space was recorded after the launch of theunmanned V-2 rocket designed by W. von Braun (USA, 1946) followed by TVimages from the low Earth orbit Television Infrared Observation Satellites (e.g.TIROS-1, 1st April 1960). The first visual observations of cloud fields from spacewere reported by the first cosmonaut, Y. A. Gagarin, who orbited the Earth on theVostok spacecraft (12th April 1961). Photo, video, and hand-held spectrometry ofcloudfieldsfromnumerousmannedSovietandAmericanspacecraftsoonfollowed.However, the era of quantitative long-term cloud observations from space beganonly 30 years ago with the launch of the first TIROS-N satellite (13th October,1978). This was an experimental satellite developed by NASA and operated byNOAA. It carried a 4-channel Advanced Very High Resolution Radiometer(AVHRR) to provide day and night cloud top and sea surface temperatures, aswell as ice and snow conditions; an atmospheric sounding system (TOVS–TIROSOperational Vertical Sounder) to provide profiles of temperature and water vapourfrom the Earth’s surface to the top of the atmosphere. Since then, many imaging