Ice depolarization statistics for 19-GHz satellite-to-earth propagation

Observations were made at 19 GHz of depolarization due to ice crystals along a satellite-earth path with a
38.6\deg
elevation angle. The one-year data base included sufficient information to determine depolarization for any incident polarization angle. Depolarization was often observed in the absence of significant rain-produced copolarized signal attenuation. This depolarization is caused by ice crystals whose symmetry axes, as observed in the plane perpendicular to the direction of propagation, were usually within
5\deg
of vertical and horizontal. Maximum depolarization was observed for
45\deg
linear or circular polarizations, and never exceeded -16 dB. For vertical and horizontal incident polarizations 8-10-dB lower maximum depolarization values were observed. Depolarization due to ice was also observed during most rain attenuation events. The unknown differential phase characteristics of rain-produced depolarization prevent further exact analysis of this ice depolarization.