A Method of Radiometric Measurements of Cloud Attenuation

Cloud attenuation has a non-negligible impact on radio waves propagating over an earth-space path, especially in high frequency signals of the satellite communication system. A precise cloud attenuation method that has mid-latitude regions applicability is presented in this paper, using the HATPRO microwave radiometer's data particularly cloud liquid water density profiles. The result indicates that the effect of cloud attenuation enlarges rapidly as the frequency increases. More than 10 dB is caused due to cloud for 99.99% link availability at high bands. It is useful to relate the calculated cloud attenuation to integrated liquid water content,and the relationship is modeled by solid line. Predictions made with the method are compared with cloud attenuation data calculated by ITU-R (The ITU Radio communication sector) model, suggesting that the ITU-R model underestimates the effect of cloud attenuation in Wuhan area, resulting from the model's underestimation of integrated liquid water content.