An analysis of a hail case over the Yangtze and Huai River Basin based on dual-polarization radar observations

In order to better understand the hail and three-body scattering signature, improve the ability of operational warning and lay the foundation of automatic hail identification on the ground based on dual-polarization radar, a hail case observed by the S-band polarimetric radar on 20 March 2019 is used to examine the observational signature and microphysical process. The result shows that: (1) During the mature stage, the hailstorm has high echo top and strong echo area aloft that are characterized by negative Z_DR (＜−0.5 dB), low ρ_hv (~0.9) and negative K_DP caused by backscattering phase, indicating that hails existing within this area are reasonably identified by HCA; (2) during the period of hail falling on the ground, the reflectivity in high levels decreases, the strong echo area descends close to the ground, and ρ_hv below the melting level increases, indicating that the size of ice particles falling from high levels decreases; hails fall to the ground at the time when the hails identified by HCA is decreasing; (3) the probability density distributions (PDD) of Z_H, ρ_hv and (SD (Z_H)) within three-body scattering signature are similar to that in North American, and the PDD of Z_DR tends to be more negative, while the range of distribution for SD (φ_DP) is about twice that in North America.