0°C isotherm height Distribution for Earth-space communication satellite links in Nigeria

Abstract

For an optimum performance of Earth-space satellite communication links, a number of meteorological parameters along the Earth-space path for specific locations are needed to be put into consideration; among such factors is the height of the 0°C isotherm (freezing level height). Information regarding this parameter is always based on the Recommendation ITU-R P.839 in the form of contour maps. Since the meteorological parameters are location dependent; there is a need for the establishment of these parameters to specific locations. In addition, ITU-R model uses a yearly averaged constant rain height for the attenuation estimation which may not be appropriate for tropical regions. In this work, the 0°C Isotherm (ZDI) height has been established using two years of data collected on-board the Precipitation radar of the Tropical Rain Measuring Mission (TRMM) satellite. The result shows the seasonal dependence of the 0°C isotherm height. It was observed among other things that the height is higher during the wet season as compared to the dry seasons. Rain-induced attenuation at frequencies above 10 GHz was also estimated using the 0°C isotherm height derived for each of the locations over the elevation angle of the NIGCOMSAT-1R in Nigeria