Prediction of depolarisation distributions on Earth-space paths

By using the theoretical relationship between attenuation and depolarisation, a cumulative distribution of depolarisation can be predicted from a distribution of attenuation at the same frequency. In the case of Earth-space paths, however, it was found that there is poor correlation between measured attenuation and XPD because of so-called ice depolarisation. This implies that the predicted XPD value for an Earth-space path includes an error if the theoretical relationship between rain attenuation and XPD is used. In this paper, a new method of predicting cumulative distributions of XPD is proposed in which the effects of the ice depolarisation are taken into consideration by using the factor of ´ice depolarisation ratio´. The applicability of this depolarisation prediction method is verified by using attenuation and depolarisation statistics which have been measured in some wave propagation experiments along Earth-space paths.