Frequency dependence of microwave depolarization versus rain attenuation

Calculations using oblate spheroidal raindrops, as well as measured data, demonstrated that rain-induced cross polarization amplitude is inversely proportional to frequency from 10 to 30 GHz. Except for extremely low rain rates (
\leq2.5
mm/h), the above frequency dependence has now been found to be true also for the more realistic (Pruppacher and Pitter shape) raindrops. Possible explanation for the misleading claim of inverse three-halves power frequency dependence was also explored. This clarification is presented to revise the frequency dependence of the International Radio Consultative Committee (CCIR) formula on rain-induced cross polarization versus attenuation.