Analysis of Doppler radar echo characteristics of a hail process on plateau of northwest Yunnan

Doppler radar echo data of Lijiang and Micaps conventional observation data were used to analyze a regional hail process occurred in the afternoon on 14 June 2011 in Lijiang city of northwest Yunnan.The main results are as follows: this hail process occurred in the weather situation that the upper atmosphere was controlled by northwest flow and lower atmosphere was influenced by convergence zone with accompanying of backflow of cool air on the surface as well as the unique topography condition.In the basic reflectivity factor figure,hail cloud echo shows the linear arrangement and patch,and hooked echo appears when development of hail cloud is too strong.On the VCS(vertical cross section) vertical profiles chart,the strong echo nucleus reaches 6-10 km highly,and presents the echo wall characteristics.On the basic radial velocity image the adverse wind area and mesoscale convergence zone can be seen in hail cloud development stage,VIL(vertically integrated liquid water content) values will be increased continuously in a leap in varying degrees before the hail occurring,and when the valures reach 35 kg.m-2 hail will begin.The upper air presenting northerly air current on the VWP(VAD wind profile) chart is chief feature when the hail appeared in Lijiang.