Modelling propagation effects in the use of S-band polarisation-diversity radars

The effects of propagation through precipitation on polarisation diversity radars at S-band are modelled. It is shown that in propagation through rain although linearly polarised waves need not be significantly affected the effect on circularly polarised returns is important. It is shown that a gate-by-gate correction process is not a satisfactory method of removing the propagation effects. However it is shown that a derived linear parameter ZDR can be obtained from the circular parameters which is less affected by propagation. The modelling is extended to targets which comprise rain and hail.