Application of the dual-polarization radar data in numerical modeling studies: Construction of the simulator

Based on the Rayleigh-Gans scattering theory,a simulator for S-band dual-linear polarization radar with the wavelength of 10 cm has been developed. The simulator considers four hydrometeors (i.e., cloud ice, snow, rain, hail), takingcloud mixing ratios and number concentrations from microphysics scheme and the axis ratio, relative dielectric constant and canting angles of particles as input, and then calculating reflectivity at horizontal and vertical polarizations, differential reflectivity, specific differential phase and others. Realistic polarimetric radar signatures of a mature 2D ideal squall-line are well produced in the simulation: Hail has high horizontal reflectivity and low differential reflectivity (Zdr hole);Zdr column in convective regions is well simulated; bright bands of horizontal reflectivity and specific differential phase show clearly in the results;and the linear relationship between the horizontal reflectivity and differential reflectivity factor of rain (rain line) is well represented. The simulator builds a direct link between model variables and polarization radar observations. In the near future, it will be used as a tool to evaluate the effect of model predictions and to directly as similate polarimetric variables into convection-resolved model.