ABSTRACT
In this chapter, the authors show the way in which microwaves can be used to measure the atmosphere, including hydrometeors, from remote instruments in general but with a clear focus on satellite systems. Measurements can therefore be made at all times of day and night, so that satellite instruments can achieve global coverage on a daily basis. The main purpose of this microwave radiometer was the measurement of the tropospheric path delay for the altimeter through the measurements of the atmospheric integrated water vapour content and the estimate of the attenuation of the altimetric signal by the liquid water content of the clouds. Atmospheric sounding from satellites was initially developed using observations of emission lines in the infrared region. The theoretical considerations for sounding the atmosphere are covered in more detail, where the authors consider different viewing geometries.
