About seasonal variations of specific attenuations derived from DSD measurements

Reliable estimates of satellite channel characteristics are of great importance for satellite communications, especially with use of even higher frequencies as Ka-band and in near future Q- and V-band. At a given rain rate the shape of rain drop size distributions (DSDs) considerably influences the corresponding specific attenuation. In previous work it was shown, that annual DSD statistics give evidence for geographical dependence. In this paper first results indicate that the seasonal variations of the DSD shapes are minor in comparison to the geographical dependencies. This points to a conclusion that a global map of annual DSD statistics will give a valuable contribution to satellite link parameter estimates.