ANALYSIS OF RADAR REFLECTIVITY, LIQUID WATER CONTENT AND RAIN RATE FOR SATELLITE LINKS APPLICATIONS IN THE TROPICS

Abstract

In recent years, higher frequencies are being adopted for radio communication and link systems design due to the congestion at the lower frequency bands. However, at these frequency bands, the atmospheric components, namely rain, liquid water content in the atmosphere, snow, atmospheric gases, hail, dust particles among others attenuate the signal. Among the atmospheric components, rain is the most significant hydrometeor that causes degradation of communication signal, especially at frequencies above 10 GHz. Hence, adequate knowledge and analysis of the radar reflectivity (Z) and rain rate (R) relation as well as liquid water content (W) and radar reflectivity (Z) relation are much desired. These are useful components in the fields of microwave communication, especially in the tropics where rain mostly contributed significantly to the degradation of radio signals in satellite communication links. In this research, Z-R and Z-W relationship for different rainfall rates over Akure, Nigeria were analyzed for a period of one year (2014). Rainfall parameters (radar reflectivity, rain rate and liquid water content) were acquired using 24.1 GHz vertically-pointing micro rain radar stationed at Physics Department, Federal University of Technology Akure, Nigeria. The study has been carried out for R ≤ 10 mm/h (stratiform) and R > 10 mm/hr (convective) rain regime at different heights interval of 0.16 km up to 0.48 km. The various functional relations between Z-R and Z-W at different heights are obtained. The study shows that Z-R and Z-W relationship varies for different rainfall rates, season wise and heights. The overall results will provide information for the design of satellite communication system that can perform well under intense weather conditions.