Abstract-Rain rate and rain attenuation predictions are one of the vital steps to be considered when analyzing a microwave satellite communication links at the Ku and Ka bands. In this paper, tools for the prediction of rain rate and rain attenuation are presented in the form of contour maps for Nigeria using a massive rainfall data bank of 30 years which are taken from measurements made from the coast to the arid region of Nigeria. Rain-rate maps for the country of Nigeria were developed using the models purposely designed for tropical zones while ITU-R models were used for the rain-attenuation maps. The information from these maps will be a good preliminary design tools for both terrestrial and earth-satellite microwave links and also provide a broad idea of rain attenuation for microwave engineers.

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Space‐borne radars are invaluable tools for characterizing clouds and precipitation. At higher frequencies (like those used for the TRMM PR or envisaged for GPM radars) attenuation due to hydrometeors increasingly becomes a relevant issue. Simultaneously when dealing with active sensors, multiple scattering effects could be significant due to the simultaneous increase of the optical thickness and the single scattering albedo of the hydrometeors with frequency. In this study, we investigate multiple scattering due to rainfall and graupel on radar returns for nadir observations at 13 and 35 GHz. A numerical approach, based on the forward fully polarized Monte Carlo technique, which incorporates a Gaussian antenna pattern function with varying beam‐widths, is adopted in the study. Results reveal that multiple scattering effects are driven by the interplay between the antenna footprint, the medium scattering coefficient and the depth traveled inside the medium. The multiple scattering effects are generally negligible at 13 GHz for typical space‐borne and air‐borne systems while they are relevant to space‐borne but almost negligible in air‐borne configurations at 35 GHz.

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Rain attenuation is .the dominant propagation impairment for high-frequency microwave systems. System design therefore requires the knowledge of the one-minute integrated-rain-rate cumulative distribution function over the coverage area in order to determine the appropriate transmitter and receiver characteristics. This paper presents a set of rain-rate contour maps, useful for link and network power sizing in Nigeria. They were developed using a combination of first-order rain-rate statistical methods: the Moupfouma-Martin model for rain-rate prediction in tropical regions, and the Rice-Holmberg model.