Abstract

Consistently required lager bandwidth at lower cost induce increases in magnitude of transmission frequency for satellite signal. This is phenomenally accompanied by proportional hydrometeors attenuation. Hence, there is need to evaluate cloud attenuation impact in every climatic region periodically. This report is one of the outcomes of experimental communication research carried out at tropical Ota (6.7oN, 3.23oE) station, southwest, Nigeria. The station spectrum analyzer measures its received beacons total attenuation at 12.245 GHz and elevation angle 59.9o to Astra satellites located at 28.2oE. Daily maximum, minimum and mean temperatures; rain amount, wind speed and direction as well as time of occurrence of each of these weather parameters were also measured. Then the radiometric data including acquired radiosonde data were analysed under rainy and non-rainy conditions, to obtain cloud attenuation contribution from the total attenuation measured per minute. The various data used range in measurement periods between four and fifty-eight years. The outputs were used to compute the station cumulative distributions for the existing cloud models and for the integrated station’s data. Statistical analysis comparing the two cumulative distributions show a high difference between the measured data and existing models’ predicted values. Hence a cloud attenuation computation algorithm and its simulation program were developed and used to derive a new tropical cloud attenuation model. The results of climatic data and analysis were used to justify the well corroborated new cloud attenuation model.

Keywords: Hydrometeors,, Cloud Attenuation,, Cloud Models,, and Tropical Climate