Deriving the linear depolarisation ratio of precipitation from copolar radar measurements

Usually, the polarisation-dependent scattering matrix is measured with the receive and transmit antennas alternately co- and crosspolarised. For scattering parameters with negligible differential phase, however, three copolar measurements can be used to obtain the complete scattering matrix. Less stringent demands on the signal-to-noise ratio are then necessary, which is especially convenient in the case of weak radar returns.