Summary
International Symposium on Antennas and Propagation
2010
Session Number:3TD4
Session:
Number:3TD4-5
Rain Attenuation Statistics and Yearly Variability of Ka and Ku Band Satellite Signals obtained for Twenty Years in Japan
Yasuyuki Maekawa,
pp.-
Publication Date:2010/11/23
Online ISSN:2188-5079
Summary:
It is well known that rain attenuation effects are significant in satellite communications and broadcast using frequency of higher than 10 GHz [1], [2]. Rain attenuation statistics are usually predicted by rainfall rate statistics observed on the ground for a long period. Typical statistical values such as rainfall rate with a yearly time percentage of 0.01% and average 0℃ height are used in the prediction methods recommended by ITU-R [3]. These statistical values of 0.01% for rainfall rate and rain attenuation, however, indicate a considerable yearly variation with the standard deviation of about 20% around the mean values [4]. Also, rain height and equivalent path length expected from the 0℃ isotherm height seem to have a similar yearly variation according to the change of average ground temperature and rainfall types. In this study, long-term rain attenuation statistics and variability are discussed using Ka and Ku band satellite signal observations conducted at Osaka Electro-Communication University in Neyagawa, Japan, from 1986 to 2006. The mean values and standard deviations of 0.01% values of rainfall rate and rain attenuation are presented for the entire observational period, and their distributions are described in terms of normal distributions. The worst month statistics are then examined for the cumulative time percentages in each year, and their variability is also discussed in relation to rainfall statistics. Finally, a yearly variation of equi-probability values between rainfall rate and rain attenuation and its relationship with equivalent path length are investigated.