Estimation of rain attenuation characteristics of satellite communication links using x-band meteorological radars

Rain attenuation characteristics of the Ku-band up-link satellite signals are presented for the past four years of 2003-2006 in Japan and Indonesia, using Japan´s domestic communication satellite Superbird C that connects Research Institute for Sustainable Humanosphere of Kyoto University (RISH) to Equatorial Atmosphere Radar Observatory (EAR). Compared with the rainfall rates with the same time percentages, equivalent path lengths of the satellite signal against the rain area are shown to be reduced down to 2 km at EAR, which is remarkably shorter than those at RISH in Japan. The almost same attenuation values and annual statistics are, however, obtained from the X-band radar observations simultaneously conducted at EAR. This suggests that long-term radar observations of convective clouds are effective to estimate rain attenuation statistics of the satellite signals in the tropical regions.