中文摘要：

利用1960—2009年气象观测资料,对安徽省128次龙卷的气候特征和环流背景进行了分析,结果表明,龙卷多发于4-9月平原丘陵地带的江淮东部,而山区极少,20世纪80年代以后龙卷明显减少;建立了安徽出现龙卷的4种概念模型。同时,利用日本JMA 20km×20km高分辨率数值预报再分析产品对比分析了龙卷、冰雹及雷雨大风的环境场,发现龙卷与冰雹、雷雨大风在4个方面存在明显差异,即中低层比湿、中低层垂直风切变、风暴相对螺旋度和0℃层以下的对流有效位能与整层对流有效位能比值,前3个均是龙卷最大,龙卷是冰雹和雷雨大风的2倍～3倍,对流有效位能主要集中在0℃层以下,而冰雹和雷雨大风主要集中在0℃层以上。基于龙卷临近预警和安徽6次龙卷的雷达特征显示,龙卷涡旋TVS的底部达到雷达最低仰角探测高度的中气旋及其后龙卷涡旋特征是识别龙卷的主要依据,龙卷触地前中气旋的最大速度差增强,其强度与龙卷强度呈正相关。而雷达距离的选取也直接影响龙卷的临近预警,距离龙卷20～100km处的雷达较为理想,200km以外的雷达资料对龙卷预警几乎没有意义。

英文摘要：

Using the historical observation data from 1960to 2009the climatic characteristics and in Anhui tornado have been analyzed.The results show that the occurring frequency of tornado in Anhui Province is more than that of the east of Changjiang-Huaihe valleys and no mountainous area from April to September.And tornadoes have obviously reduced since 1980s.Four types of synoptic situation which form tornadoes probably to have been summarized too.Through the contrastive analyses of the difference of tornado,hail and gust with thunderstorm using 20km×20km JMA reanalysis products,the conclusions are as follows：Before the tornado occurring,the air on the low-level is warm and wet,sometime is wet in whole layer.Lifting condensation level is lower.CAPE main is from below 0 ℃level.There is strong vertical wind shear in middle-lower levels and the value of storm relative helix is large.Tornado pre-warning depends mostly on velocity field from Doppler radar.The identifying characteristics of tornado are mesocycle and TVS（TVS often can be identified）.The mesocycle or TVS almost is in the lowest height detected by radar.The positive/negative difference of Doppler velocity is becoming larger and its height lower during TVS evolution.And velocity difference is the largest when the tornado touches on the ground.Other influencing factor of tornado pre-warning is the distance from tornado position to Doppler radar,the ideal distance is between 20km and 100km.