Satellite-ground signal depolarisation at millimetre wavelengths through thunderstorms

Measurements are reported of 30 GHz signal fading and depolarisation occurring on a satellite-ground link during a period of severe thunderstorm activity. Simultaneous observations of the storms using both a p.p.i. and a fixed-beam radar provide further evidence of the severe depolarisation caused by hydrometeors above the freezing layer, and evidence is presented of abrupt changes in the level of depolarisation, which are associated with lightning strokes.