Scattering Effects on Microwave Passive Remote Sensing of Cloud Parameters

As an important tool of atmospheric remote sensing, microwave radiometers are used for temperature profiling, and vapor and liquid column measurements (Hogg et al. 1983; Solheim et al.1998). Radiometer measurements are inexpensive compared to the cost of radar, and it can provide all-time observation in both cloudy and clear air situations. However, using radiometer measurements can be more difficult than a radar measurement because: (1) the measured brightness temperature is proportional to cumulative emission from various layers; (11) both scattering and absorption contribute to the measured radiation, which is governed by an integraldifferential Radiative Transfer (RT) equation; (iii) the relation between brightness temperature and the atmospheric parameters is non-linear. Therefore, linear and log-linear models have limited applicability.