【摘要】 利用多普勒雷达资料,对发生在安徽的3次强烈龙卷过程进行了分析。重点研究了导致F2~F3级强龙卷的3次超级单体风暴多普勒雷达回波特征及其与强冰雹超级单体风暴的差异。另外,利用安徽省、市、县气象报表、历年气候评价灾情资料(部分来自民政部门的灾情报告),对1960年至今的龙卷天气的时空分布及变化趋势、产生龙卷的环流形势特征进行了分析,结果表明:(1)龙卷主要出现在淮北东部和江淮之间东部地势平坦地区,7月份出现龙卷的概率最高。(2)超级单体龙卷产生在中等大小的对流有效位能和强垂直风切变条件下,同时抬升凝结高度较低。(3)3次F2~F3级龙卷在发生前、发生时在多普勒雷达上都探测到强中气旋和龙卷涡旋特征TVS。与非龙卷超级单体风暴相比,导致强龙卷的中气旋底高明显偏低,基本在1 km以下。同时风暴结构也有所不同,造成龙卷天气的超级单体风暴最大反射率因子与风暴质心高度接近,基本在3 km左右,反射率因子在50~60 dBz。造成强冰雹的超级单体风暴在冰雹产生前,风暴最大反射率因子高于风暴质心的高度;当风暴开始降雹时,最大反射率因子高度开始降低,而风暴质心的高度变化不大,高于最大反射率因子高度,基本保持在5km左右,反射率因子在60~70 dBz。更多还原

【Abstract】 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.更多还原