Characteristic Analysis and Early-Warning of Tornado Supercell Storm

Usingthe Doppler radar data,three severe tornado processes occurred inAnhui were analyzed.The characteristics of Doppler base reflectivity in these F2~F3 tornados caused by supercell stormand the difference between tornado and hail supercellstormswere mainly studied.In addition,the meteorologicdata of 80 observations in Anhuiand the disaster dataof climate evaluation in past years,partlyfrom the disaster reportsof civil administration,were used.Based on these data,not only the space-time distributions and its variation trendof tornado processes,but alsothe circulation situationforming tornados from1960 up to nowwere researched.Theresults show that:(1) Tornados mainly occurred in plain places from east of Huaibei to east of Jianghuai region.The highest probabilityof tornados taking place were in July.(2) The supercell tornado occurred under the conditionof middleCAPE and severe vertical wind shear.Atthe same time its lifting condensation levelwas lower.(3) The three F2~F3 tornados all detected evere meso-cyclone and TVS(Tornadic Vortex Signature)at radar before and during occurrence.Comparing with non-tornado supercellstorm,the bottom height of meso-cyclonecausing severe tornados were obvious lower,mostly lower than 1 km.Atthe same timethe storm structure also had difference.The maximum reflectivityof supercell storm causing tornado is near to storm centroidat height,basicallyat 3 km or so,and the reflectivity was within 50~60 dBz.But for severe hail supercell storm,themaximum reflectivitywas higher than the storm centroidat heightbefore the storm disaster.When hailing,the height of maximum reflectivity became lower,but the height of storm centroidhad no change which was higher than the maximum reflectivity,keeping at 5 km or so and the reflectivity within60~70 dBz.