| In this paper, firstly, by means of analyzing some rain attenuation experimental results, the raindrop size distributions applied to various climatic regions in China, are discussed. At short microwave and long millimeter wave bands, the ratios of the rain-induced attenuation on up-link to down-link are estimated on earth-space slant paths. A comparison of the prediction results with the experiment data in Boston and Kashima areas is carried out.Secondly, a more practical water-coated ice sphere model of melting particles has been given. Based on this model, the scattering properties and albedo WQ of melting particles have been calculated by use of the coated sphere BHCOAT method. It is shown that the albedo of melting particles may be more than the raindrops and snow spheres at C, X and Ku-band. These results are in agreement with the conclusion observed by radar and given in literature. It demonstrates that the water-coated snow sphere model of melting particles is appropriate and practicable. The specify attenuation, attenuation and scattering impairment of a melting layer have also been predicted at various rainfall for 6, 10, 20, 30GHz. The results calculated show that the attenuation due to melting layer are more than the attenuation induced by the identical thickness rain. The scattering impairment due to a melting layer are also more than rain and snow at 6, lOGGHz, and at the 20, 30GHz slightly more than the rain.Thirdly, the macro- and micro-physical properties of clouds over Xi'an region are discussed based on meteorologic observation data. According to statistics parameters of the typical clouds over Xi'an region and cloud data obtained from the global distribution of cloud cover under the auspices of World Meteorological Organization, for Xi'an region typical cloud, the parameters of Khragian-Mazin cloud drop size distribution are obtained. Based on Xi'an cloud water content profile, on Earth-space paths, attenuation due to cloud are calculated by means of the K-M distribution. It is shown that the attenuation induced by cloud are taken into account at Ka- at elevation angle smaller than 30 and V-band paths. The theory and mechanism of backscattering for clouds are analyzed. For 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 average cloud diameter, clear-air and humidity turbulence and also from distributions of cloud particles, especially, at higher frequencies.Fourthly, by an analysis of log-amplitude scintillation due to troposphere turbulent, it is shown that the relative humidity and temperature are the major factor impacted on log-amplitude scintillation, at microwave and millimeter-wave band. An atmosphere structure constant Cn2 model, which varies with height, is presented based on ITU-R amplitude scintillation model, existing ITU-R optical Cn2 model and meteorologic measurement relative humidity and temperature profile data, at 10~30GHz. The log-amplitude scintillation deviation calculated in terms of the Cn2 model based on humidity and temperature vertical profile compare with values predicted by means ofITU-R and Ortgies model. It is emerged that the calculation results based on the Cn2 model agree almost with prediction results by ITU-R and Ortgies model at 10~30GHz and there is an advantage that relative humidity and temperature varied with height has be considered in the Cn2 model. Therefore, it is shown that the C,,2 model is usable and is more practical. Based on Xi'an region meteorologic measurement relative humidity and temperature profile data in cloud cover, the log-amplitude scintillation deviation a, calculated in terms of the Cn2 model compare with values predicted by means of Ortgies model at 10~30GHz. It is shown that the C,,2 model can be applied at the continental climate area as Xi'an area.Finally, on Earth-space paths, by applying a modif...
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