Separation of rain and ice contributions to depolarization on slant path links

Rain and atmospheric ice crystals are the main causes of signal depolarization on Earth-satellite communication links, the degradation effects being stronger as frequency increases. However, the actual impact of ice on path depolarization has not been yet clearly assessed. Current prediction methods aimed at determining long-term statistics of crosspolar discrimination (XPD) above 10 GHz fail to give good estimates, mainly due to the improper account of the effect of ice crystals. In this paper, a procedure is applied to separate and assess the individual contributions of rain and ice to depolarization events. These results lead to the formulation of a method to retrieve a fundamental ice medium parameter, the effective ice crystal content. The analysis is performed on data recorded during the propagation experiments with ESA's Olympus satellite in Belgium. Results of ice-rain separation and of ice crystal content are presented and discussed. The impact of ice on XPD is highlighted.