Targeting at processing and analyzing the data of millimeter-wave radars

backscattering and extinction cross sections of non-spherical ice crystals are obtained and parameterized using Discrete Dipole Approximation（DDA） method.Sampling for 1330 times（representing 1330 Particles Size Distribution（PSD） of ice crystals）

attenuation coefficient（k） and radar reflectivity factor（Z e） are calculated based on a refined model for representing the ice hydrometeors by assuming gamma PSD.The accurate formulas of k-Z e relationships are derived using numerical simulation for W（94 GHz） and Ka（35 GHz） band radar.The results show that non-spherical and non-Rayleigh scattering effects of ice crystals on 94 GHz radar attenuation are larger than that on 35 GHz.The attenuation at 94 GHz is more than that at 35 GHz with the same PSD

and that the impacts of ice clouds models on k-Z e relations are remarkable.The results may be suitable for attenuation correction of non-precipitating ice clouds in midlatitude for millimeter-wave radars and provide a reference for millimeter-wave cloud radars in China.