Development of Cloud Attenuation Model for Satellite Network Links Performance Improvement

This paper provides a review of cloud attenuation modelling, using as a case study, a typical research effort done to construct a cloud attenuation model for tropical Ota (6.7oN, 3.23oE), southwest Nigeria. Improvement of the satellite services availability in every locality is fundamental. All local climate areas must build useful climatic models, such as the cloud attenuation model, which can be used to determine local link margins for satellite network services in particular locations and serve as correlative resources to applications on global satellites. Effects of suspended water droplets (SWD) and suspended ice crystals (SIC), which make up clouds, are a significant concern in the design and successful operation of satellite communication systems at frequencies above 3GHz, because the hydrometeors significantly reduce the services availability as frequency increases. For the purpose of simulating cloud attenuation at a station, the climatic initial and boundary conditions are taken into account as well as the cloud's numerical representations to derive the cloud's parametric system equation. The numerical representations are based on climatological and radiometric data that have been gathered through well-designed experiments, in which cloud parameters are measured using radiance changes tracked by satellites and visually observed surface stations on land and ships in the ocean. The ongoing research project started with an examination of eight foundational cloud models at the station, through investigation of the radiosonde and cloud cover data. Then, the study of spectrum analyzer’s data on signal attenuation that has been gathered over a three-year period is examined. The station data from the beacon transmission experiment to and from the Astra satellite at 28.2oE were then analyzed and modelled. This entails comparing the cumulative attenuation distribution curves of the spectrum analyzer data and those of the station's existing cloud models with the cumulative attenuation distribution curves of output data generated by each run session of the station simulation equation program. The general representation of the station cloud attenuation model is given, as well as further modelling development and future work. A single global satellite based climatic model is desirable, where modular algorithm would be used to integrate the various climatic area models.