Analysis of Doppler Radar echo characteristics about hail in Plateau of northwest Yunnan

Doppler radar echo characteristics of hail are analyzed with Doppler radar echo data of 31 times hail in Lijiang City,Plateau of northwest Yunnan in 2006 to 2010.The main results are as follow:① Hail cloud echo has a higher value of base reflectivity factor,mature stage of hail clouds mostly showing points,massive,banded in the PPI graph,and intense hail sometimes appears the hook echo,line echo,bow echoes,V notch,finger-like echo and three-body scattering phenomena etc.②In the VCS vertical profiles,hail cloud echo has high intensity echo nuclear,and its structural features are: drape-shaped,dome,echo wall,bounded weak echo region(BWER) or weak echo region(WER) and so on.③Hail cloud echo's velocity field appeared such characteristics as convergence zone,adverse wind area.④ VIL values will continue to increase in a leap in varying degrees before the hail,and reach maximum after began to hail;It will have a convective weather when VIL values greater than 22 kg/m2or a hail weather when VIL values greater than 35 kg/m2.