球锥扁椭球冰粒后向散射实验与DDA计算研究

采用实验室观测和DDA法理论计算，分别获得了球锥扁椭球形冰粒对3.2、5.6和10.7cm三种波长极化波的后向散射特性数据。结果表明，测量资料和计算数据具有很好的一致性。球锥扁椭球形冰粒的后向散射截面大小不仅依赖于其尺寸（等容半径）而且受其形状影响，“差反射率雷因子ZDR”与粒子形状参数“水平-垂直尺度比”呈很好的线性正相关。这是利用双偏振雷达探测识别球锥扁椭球形冰雹的依据。

Lab Observation and DDA Computation on the Backscattering Featuresof Sphere-Cone-Oblate Ice Particles

The measuring experiment and DDA calculations for the scattering of ice particles are briefly presented in this paper. Twenty sphere-cone-oblate ice particles are simulated for lab observations and DDA calculations.Theoretical results are compared with the experiment data obtained with a microwave measuring system.It is shown that the theoretical results are consistent with the experiment data in general.As a result,the reliability of theoretical model is proved.Theoretical and experimental analyses indicate that the backscattering ability of sphere-cone-oblate ice particles increases as the particle size parameter increases,and fluctuates in the so-called resonance region.The backscattering cross-sections of sphere-cone-oblate ice particles depend upon not only their sizes(equivolume spherical radii R e)but also their shapes.There is a linear relationship between differential reflectivity Z DR and the shape factor which is defined as the ratio of the horizontal scale to the vertical scale of a particle.