Alternate transmission of+45 degrees and-45 degrees slant polarization andsimultaneous reception of vertical and horizontal polarization for precipitation measurement

A polarimetric weather radar with alternate transmission of slant linear +4 5 degrees and -45 degrees polarization and simultaneous reception of both l inear vertical and Linear horizontal polarization is considered. The equati ons of the radar observables for a model medium containing nonspherical hyd rometeors are presented. Assuming the hydrometeors to be axially symmetric with a canting angle distribution symmetric about the mean canting-angle, a set of equations for separation of propagation and backscattering effects is developed. The mean apparent canting angle, the degree of common orienta tion of the hydrometeors, and the differential phase shift are obtained. Us ing empirical relationships, the mean and differential attenuations are est imated by means of the differential phase shift. The intrinsic value of the reflectivity, the differential reflectivity and the copolar correlation co efficient at zero lag time are then determined. Application of this to a mo del convective rain cell shows that the use of simultaneous transmission an d reception of linear vertical and Linear horizontal polarization at S, C, and X bands provides accurate estimates of the intrinsic scattering propert ies of precipitation. The analysis of the bins on the radar observables due to the assumption of a medium of equioriented hydrometeors shows that all the observables with the exception of reflectivity can he severely affected .