Rain height information from TRMM precipitation radar and micro rain radar for radio communication studies in Nigeria

Abstract

One of the key meteorological parameters necessary for estimating fade margins for link availability in the satellite-Earth propagation path is the 0°C isotherm height or the rain height. Although, ITU-R P. 839-3 recommendation provided a global map of this height in the form of contours at a resolution of 1.5° by 1.5° in both latitude and longitude in regions of the world where no location specific information is available. However, the precipitation structure depends on the different climatic region, which makes rain height to be strongly depended on the local weather. In this report, we present information on rain characteristics of 0°C isotherm height in Nigeria based on 2 years of precipitation data obtained from the Tropical Rain Measuring Mission (TRMM) satellite. The analysis has been carried out based on the stratiform rain events which normally exhibit a characterized melting layer or bright-band. These results are compared with a measurement from ground-based vertically looking micro rain radar (MRR) and the mean 0°C isotherm height provided by the ITU-R P. 839-3 recommendations. It is worth underlined that-an annual mean height given by the ITU-R for this region shows an average percentage difference of about 4% of the measured values. This suggests that fade margin estimated using the ITU-recommended value of this region will be overestimated. In overall, rain height obtained from TRMM-PR is in agreement with the ground-based radar.