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Introduction of satellite services using higher frequency bands such as Ku- and Ka-band requires the characterization of tropospheric propagation factors that are normally considered negligible at lower frequency bands. Clouds scattering and attenuation are considered one such factor. Clouds are present during a large fraction of an average year and cloud scattering and attenuation, together with gaseous absorption, will determine the system performance under non-rainy conditions. In this paper, macro- and micro-physical properties of clouds over Xi'an region are discussed based on meteorologic observation data. The theory and mechanism of backscattering for clouds are analyzed. According to statistics parameters of the clouds over Xi'an region, the quantity calculations of the backscattering cross sections for various reflection mechanism of cloud are dealt with. The results calculated show that the major contributions for the backscattering cross section come possibly from clear-air and humidity turbulence and also from distributions of cloud particles, especially, at higher frequencies. These quantification calculation results on the basis of Xi'an typical clouds properties confirm previous results and it is significance for satellite communication systems, particularly, low availability satellite links and active and passive remote sensing, etc.
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