Effects of rain area motions and ground wind velocities on rain attenuation characteristics of Ku-band satellite signals

Speeds and directions of the motion of rain areas that cause the attenuation of Ku-band satellite communications links are estimated from the broadcast satellite (BS) signal levels simultaneously obtained at Osaka Electro-Communication University (OECU; Neyagawa, Osaka), the Research Institute for Sustainable Humanosphere (RISH; Uji, Kyoto) and the Shigaraki MU radar observatory (Koga, Shiga) of Kyoto University. The speeds and directions of rain area motion are compared with the ground wind velocities observed by a nearby AMeDAS station from 2008 to 2011. A correlation coefficients of nearly 0.6 is found between the directions of the rain area motions and the ground wind velocities although the directions tend to be rotated slightly anti-clockwise on the ground. Thus, the AMeDAS data seems to be important to determine the direction of satellite stations when the site diversity techniques are conducted.