“2012.4.11”两个强降雹超级单体特征分析  

Analysis of Two Severe Hail Supercell Storms on 11 April 2012

作　　者：陈秋萍[1] 陈齐川[1] 冯晋勤 黄铃光[1] 

机构地区：[1]福建省气象台,福州350001 [2]福建省龙岩市气象局,龙岩364000

出　　处：《气象》2015年第1期25-33,共9页Meteorological Monthly

基　　金：福建省自然科学基金项目(2010J01244和2014J01148)共同资助

摘　　要：利用常规气象资料、自动站资料、新一代天气雷达和风廓线雷达等资料,对一次强对流天气过程中两个强风暴单体的形势背景、强对流发生条件、强风暴单体演变及结构特征、风暴异同点进行了详细分析。结果表明:(1)本次强对流过程是发生在强的垂直风切变条件下;高层冷平流降温减湿、低层暖平流增温增湿的对流不稳定层结,高CAPE值为强对流发生发展提供了必要的能量条件;上干下湿的水汽分布有利于冰雹、雷暴大风的产生;适宜的0℃、-20℃层高度使此次过程地面以降雹为主;地面倒槽低压、辐合线及低层锋区的南压是这次强对流天气的触发因子。(2)两个强降雹单体雷达回波共同特征是降大雹前均出现了三体散射长钉回波,弱回波区,回波强度强,VIL密度均大于4 kg·m^(-3),成熟阶段均右偏高空风约30°。(3)长生命史超级单体风暴Ⅱ的中气旋维持2个多小时,它保证了一支强上升气流支撑空中大冰雹的增长,维持了雷暴的持续发展,使其生命史长达近6 h,同时也存在前侧、后侧入流缺口,反映了上升气流与下沉气流共存的风暴动力特征,其高层辐散更强,移动路径东略偏南且移向稳定,平均右偏高空风约28°,移速均匀为14 m·s^(-1);超级单体风暴Ⅰ的中气旋维持时间仅十几分钟,且处于弱中气旋的下限,其高层辐散和上升气流更弱,风暴生命史更短,移动路径东略偏北,除成熟阶段外右偏高空风10°~20°。这些差异与产生风暴的环境条件如垂直风切变、垂直涡度等存在差异有密切关系。Using conventional and intense automatic observation,LINK AD/SA and wind profiler radar data,the environmental conditions,structures and evolution of two supercell storms are analyzed.The results are as follows:(1) Favorable conditions for the severe convective weather process are large vertical wind shear,high-level cold and low-level warm,high-level dry and low-level moist,right height of 0℃ and— 20℃ layer and large convective available potential energy(CAPE).The trigger of the severe convective weather is low-pressure on surface,convergence line,low-level frontal zone.(2) The common characteristics of the two supercell storms are three-body scatter,weak echo areas,stronger echo intensity,VIL density value over A kg · m^(-3),and moving rightward 30° with upper-wind in the mature stage.(3) The meso cyclone of long life supercell storm Ⅱ lasts more than 2 h.strong updraft causes hails to grow,and stormⅡ lasts 6 h.At the same time,high-level divergence is longer.Meso cyclone of supercell storm Ⅰ lasts only 18 min,high-level divergence and updraft are weak,and their lives are short.These differences are closely bound up with the environmental conditions such as vertical wind shear and vertical vorticity.

关 键 词：超级单体 中气旋 三体散射 垂直风切变 相对风暴螺旋度 

分 类 号：P458.121.2[天文地球—大气科学及气象学]