Retrieval of sun brightness temperature and precipitating cloud extinction using ground-based sun-tracking microwave radiometry
Sun-tracking (ST) microwave radiometry is a technique where the Sun is used as a microwave signal source and it is here rigorously summarized. The antenna noise temperature of a ground-based microwave radiometer is measured by alternately pointing toward-the-Sun and off-the-Sun while tracking it along its diurnal ecliptic. During clear sky the brightness temperature of the Sun disk emission at K and Ka band and in the unexplored millimeter-wave frequency region at V and W band can be estimated by adopting different techniques.