Study of Hail with C B and Dual Linear Polarization Radar
Liu Liping Xu Baoxiang Wang Zhijun Wang Jun(Lanzhou Institute of Plateau Atomspheric Physics , Chinese Academy of Sciences , Lanzhou 730001 )
This paper presents the calculations of the scattering properties of hydrometeors with different shapes and phases. Based on these properties and ZDR features of rain and clond echos, the dual linear polarization radar RHI data observed during hailstorm processes on August 9 and August 30, 1990 are analysed . We deduced that the area with negative ZDR values corresponded to hail shafts where may appear large oblate hailstones and small conical hailstones, and the area with great positive Z D R values corresponded to raining area . The Z D R greater than 5dB was caused by huge raindrops (D0.5cm). It is possible to detect the presence of hail using ZDR as a criterion. Compared with a S-band radar, the C-band dual linear polarization radar is unique in several aspects : the Z DR values are larger in raining area and smaller and negative in hail shooting area , which are useful for the study of microphysics and spatial structure of storms. The dual linear polarization radar will be impartant to cloud physics and weather modification .