Interpretation of polarimetric radar covariance matrix for meteorological scatterers

Modern dual-polarization radars provide the unique capability to measure the fields of all components of the covariance backscattering matrix including co-cross-polar correlation coefficients that haven´t been explored much for linearly polarized radars. The authors present full polarimetric examples of such data obtained with the CSU CHILL and NCAR S-Pol research polarimetric radars. Both radars operate at the wavelengths of about 10 cm. The radars have two receivers that allow to measure simultaneously co-polar and cross-polar components of the backscattered electromagnetic wave. At least ten radar variables can be obtained simultaneously: radar reflectivity factor Z, differential reflectivity Z_DR, linear depolarization ratio LDR total differential phase Φ_DP, specific differential phase K_DP, cross-correlation coefficient ρ_hv, and the magnitudes and the phases of the two co-cross-polar correlation coefficients |ρ_xh| (|ρ_xv|) and arg(ρ _xh) (arg(ρ_xv)) respectively. First six variables have been studied quite well in the literature, whereas the information content of the co-cross-polar correlation coefficients ρ _xh and ρ_xv needs to be examined. This is a major focus of this study