Rainrate and rain attenuation statistics for different homogeneous regions of India

Abstract

Rain rate and rain attenuation predictions are one of the most important steps to be considered when analyzing satellite communication links at the Ku and Ka bands. Rain rate distributions are calculated from the global data sets of Tropical Rainfall Measuring Mission (TRMM) and Global Precipitation Climatology Project (GPCP) for six rainfall homogeneous regions of India. The rain rate distributions are estimated from the monthly accumulations of TRMM and GPCP for the years 1998-2010. The estimated rain rate distributions are compared with the standard ITU-R P.837-5 (International Telecommunication Union - for Radio wave propagation) and observed relative errors are presented. The specific rain attenuation calculated at 0.01% and 0.001% probabilities of exceedance in an average year for different frequencies are also presented for the six homogeneous regions of India. Observations indicate maximum specific attenuation in the NE region over Cheerapunji at 0.001% of the time, and minimum attenuation of 21.988 dB km^-1 in Bikaner at 0.01% for 50 GHz frequency in the NW region. Rain attenuation and rain rate distribution are found to exhibit similar characteristics over six homogeneous regions of India.