Scattering Of Microwaves By Non-spherical Raindrops And Hails

In the first, the backscattering cross-sections of liquid and ice oblates and sphere-cone-oblate ice particles simulated for lab observations, are calculated by the discrete-dipole approximation (DDA) and the T-matrix method. The 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. Theoretical and experimental analyses indicate that the backscattering ability of nonspherical raindrops and ice particles presents a curved change as the particle size 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 but also their shapes. There is a linear relationship between differential reflectivity ZDR and the shape factor defined as the ratio of the horizontal scale to the vertical scale of a particle. Secondly, This paper theoretically examines the properties of reflectivity ZHH, differential reflectivity ZDR and the linear depolarization factor LDR of rain and hail at 3.2cm, 5.6cm and 10.7cm wavelengths. The computation has been performed for the precipitation particles having different shapes, orientations, densities, water contents, and water coatings. The results should prove useful for interpreting radar measurements. Moreover, the scattering features of the cluster consisting of several non-overlapping, external spheres are briefly discussed.