Cloud attenuation on Earth-Space path at some provincial capital cities in South Africa

Abstract

Cloud attenuation is one of the crucial parameters in deciding the fade margin for satellite communication systems at higher frequencies. In this paper, five-year analyses of cloud-based attenuation in the microwave and millimeter-wave path over the two largest and provincial capital cities in South Africa, a subtropical region were presented. The result shows that some important aspects of clouds were location and monthly-dependent. Over the studied locations, the mean cloud value observed is between 5.40% and 24.60%, the rainfall amount ranges from 4.42 to 129.87 mm, and the relative humidity ranges from 24% to 69%. The cloud attenuation and specific attenuation coefficient increases with frequency. Additionally, around 1 dB and beyond was recorded at frequencies above 60 GHz. This work indicates that the Cloud Liquid Water Content (CLWC) affects radio signals in a more significant way. Attenuating factors affecting attenuation may include the CLWC and some important features of clouds over the study cities.