Frequency dependence of absorption attenuation due to hydrometeors

In radio wave propagation problems, the attenuation of the electromagnetic signal is due to two phenomena. In the presence of hydrometeors, rain, hail or fog, the energy of the propagating wave will be scattered and also the dielectric losses in the hydrometeors will absorb power from the wave. Both these extinction mechanisms are frequency dependent, especially scattering in the low-frequency region. The variation of the hydrometeor attenuation with frequency is discussed theoretically. It is to be noted that the dielectric behaviour of water as continuous liquid differs much from the behaviour as raindrops. This can be analysed with dielectric mixing theories developed by the author