Twenty sphere-cone-oblate ice particles are simulated for their backscattering observations in a microwave lab and calculations are done with the DDA method.The lab experiment and the DDA theory are brie7ypresented in this paper.The theoretical results are compared with the lab observations.It is shown that the theoretical results are consistent with the experimental data in general and that the backscattering ability of sphere-cone-oblate ice particles increases as the particle size parameter increases,and 7uctuates in the so-called resonance region.The backscattering cross sections of sphere-cone-oblate ice particles depend not only on their sizes equivolume spherical radii Re but also on their shapes.There is a statistically linear relationship between di:erential re7ectivity ZDR and the shape factor, 2a/h,which is the ratio of the horizontal scale to the vertical scale of a particle.

This paper is devoted to the calculation of ice content-dependent,refractive index of mixed ice–water particles in clouds and precipitation from Debye's,Maxwell Garnet's and other models and the e4ects of di4erently structured particles upon microwave absorption,scattering and backscattering cross-sections.Evidence suggests that while both the real and imaginary parts of the refractive index diminish with increased ice content of such a sphere,the radiation intensity variation di4ers from one model to another.The results from the commonly used Debye's algorithm go to an extreme.Mie's theoretical calculations show that for a 7xed sized mixture its absorption cross-section may exceed that of a pure water particle of the same size.At a small physical parameter |2πmr=/λ|,the scattering cross-section decreases with increased ice content f,and at a bigger value of the parameter,the cross-section may be greater at a certain f range than that of a pure water sphere of the same volume.The absorption,scattering and backscattering cross-sections of a mixture change with f in an oscillatory manner.However,di4ering algorithms of the refractive index give di4erent oscillation's features.Since these algorithms are based on particular assumptions of the physical properties of these mixtures,our conclusions achieved here can be utilized as a reference in the study of microwave transfer and atmospheric remote sensing.