The devastating effects of rain-induced attenuation on communication links operating above 10 GHz during rainy events can significantly degrade signal quality, leading to interruptions in service and reduced data throughput. Understanding the spatial and seasonal distribution of rain heights is crucial for predicting these attenuation effects and for network performance optimization. This study utilized ten years of atmospheric temperature and geopotential height data at seven pressure levels (1000, 850, 700, 500, 300, 200, and 100 hPa) obtained from the Copernicus Climate Data Store (CDS) to deduce rain heights across nine stations in South Africa. The kernel density estimation (KDE) method was applied to estimate the temporal variation of rain height. A comparison of the measured and estimated rain heights shows a correlation coefficient of 0.997 with a maximum percentage difference of 5.3%. The results show that rain height ranges from a minimum of 3.5 km during winter in Cape Town to a maximum of about 5.27 km during the summer in Polokwane. The spatial variation shows a location-dependent seasonal trend, with peak rain heights prevailing at the low-latitude stations. The seasonal variability indicates that higher rain heights dominate in the regions (Polokwane, Pretoria, Nelspruit, Mahikeng) where there is frequent occurrence of rainfall during the winter season and vice versa. Contour maps of rain heights over the four seasons (autumn, spring, winter, and summer) were also developed for South Africa. The estimated seasonal rain heights show that rain-induced attenuations were grossly underestimated by the International Telecommunication Union (ITU) recommended rain heights at most of the stations during autumn, spring, and summer but fairly overestimated during winter. Durban had a peak attenuation of 15.9 dB during the summer, while Upington recorded the smallest attenuation of about 7.7 dB during winter at a 0.01% time exceedance. Future system planning and adjustments of existing infrastructure in the study stations could be improved by integrating these localized, seasonal radio propagation data in link budget design.

To meet the rising demand for uninterrupted high-speed broadband internet services, the deployment of high-frequency bands for the transmission of radio signals is inevitable. Unfortunately, attenuation due to rain droplets remains the most challenging factor impeding effective radio wave propagation especially in earth-space satellite links operating at Ka and V bands. It is important to understand the attenuation and the parameters that determine its magnitude in order to provide an effective solution to this problem. Rain height as one of the attenuation input parameters was examined in detail. A study of its temporal evolution reveals that seasonal variation is insignificant while the spatial variation shows that it increases from the Sahel to the Coastal Zone of Nigeria. The work provides comprehensive rain height and rain-induced attenuation contour maps. These maps are expected to serve as a database for link budget calculations for different areas in Nigeria. Rain-induced attenuation maps for 1%, 0.1%, and 0.01% of time exceedance are provided at 20 GHz and 40 GHz for Ka and V band signals respectively.

This study undertakes the determination of suitable cutoff frequency for extracting scintillation amplitude dataset from radio propagation beacons on satellite link within Akure (7.17°N, 5.18°E), Southwest Nigeria. Attempt was also made towards evaluating the spectral characteristics of scintillation parameters through power spectra density (PSD) analysis. Concurrent measurement of satellite beacon signals and meteorological parameters was carried out on Earth-space path over the location for tropospheric amplitude scintillation studies. Tektronix Y400 NetTek Analyzer and Davis Vantage Vue weather station were used for beacon and weather parameters measurements at 1 second and 1 minute integration times respectively. Data spanning one (1) year of measurement were used for the investigation. Results show that extra contributions to signal distortions by non-scintillation mechanisms during extraction of scintillation dataset from satellite radio beacon series may be eliminated by using a cutoff frequency, f c of 0.25 Hz for high pass filtering. Also, spectral slopes with lower magnitudes were found to occur more predominantly than those with higher magnitudes.

In this present era, the rising demandfor seamless wide band internetwork services such as 5G network requires the propagation of radio waves at high frequency. Rain-induced attenuation poses a lot of dangers on Earth-Space satellite links operating at frequencies above 10 GHz. Although the magnitude of overall attenuation on any radio link is determined by various natural phenomena such as atmospheric gases, fog, mist, aerosol, ice, contribution by rain remains the most significant. This paper provides extensive study on the rain heights variability in Nigeria using data obtained from the Global Precipitation Mission (GPM). The result depicts an increasing trend of rain height from 4.92 km in the southern part of the country to about 5.23 km in the north. The results show that ITU-R recommended value underestimate rain height. The results also show seasonal dependence of rain height throughout the years of study. Analysis of the GPM data shows thatfreezing heightsacross all stations were underestimated byabout 9 % when compared with previous TRMM-based research. The present study has revealed the preference of GPM data over TRMM data for the estimation of rain height and rain-induced attenuation.

The quality of services provided via Inter-Terrestrial radio communication links such as GSM networks, Wide Area Network (WAN), Radio and TV broadcasts is largely influenced by some meteorological parameters such as temperature, pressure and humidity. Proper knowledge of these parameters, specifically at microwave antenna heights (about 70m) is important in order to maintain an effective line-of-sight (LOS) link even during the worst weather conditions. The geoclimatic factor is an important quantity that must be considered in the design of terrestrial links for effective wireless communication. This work utilized satellite data from the European Center for Medium-Range Weather Forecasts (ECMWF) to compute the point refractivity gradient and geoclimatic factor for Yenagoa and its environs. The research was necessitated by the paucity of research on this subject matter for Yenegoa. The results of the research show that point refractivity gradient and geoclimatic factor in the study area vary with season. The average point refractivity gradient and geoclimatic factor at 70 m above the ground level are:136.433 N-unit/Km and 6.638633E-05 respectively. This implies that radiowaves propagating in this region at the said altitude is most likely to be super refractive in both rain and clear air atmospheric conditions. Rain or worst condition refers to the period when atmospheric components such as hydrometeor, lithometeor, aerosol have significant effects on propagated radio signals. Clear-air conditions means when maximum possible signal is received such that the most threatening atmospheric components (rain drops) have negligible effects on propagated signal. The results will be useful for radio engineers in the design and configuration of inter-terrestrial microwave links in Yenagoa and Its environs for optimum quality of service.