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2016年6月23日14—15时，江苏省阜宁县突遭"增强藤田"4级龙卷、强风、短时强降水和冰雹等强对流天气，致使99人罹难，800多人受伤，属极其罕见的极端天气事件.本文利用加密自动站数据、探空数据、单部雷达观测数据以及双多普勒雷达三维风场反演数据，研究了此次龙卷发生的天气背景、龙卷超级单体的三维结构及其演变特征.研究表明：（1）龙卷发生期间，阜宁处于地面暖湿舌内、地面有γ中尺度气旋和辐合线；环境大气抬升凝结高度很低、中低层有很强的水平风的垂直切变；这有利于龙卷的生成.（2）此次龙卷超级单体左移风暴的低层有钩状回波和入流缺口，有界弱回波区位于垂直剖面中低层、悬垂回波位于风暴前部高层.（3）龙卷发生前，风暴质心高度、最大反射率因子高度和风暴回波顶高度均持续增加，风暴垂直累积液态含水量激增；龙卷发生在上述参数的数值首次同时减小时.（4）双多普勒雷达反演的三维风场揭示，超级单体形成之前的对流风暴内部中低层已经有中尺度气旋形成，中尺度气旋伴随着超级单体的生成、发展和强化的各个阶段.中尺度气旋位于钩状回波顶端、其南端有反气旋，此涡旋偶对于中层动量下传、龙卷生成、发展、加强和触地具有重要作用. 相似文献
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1956-2011年黑龙江省龙卷风气候特征 总被引：2，自引：0，他引：2
利用富士达—皮尔森强度分类法对1956—2011年黑龙江省229个龙卷风样本进行分类,分析龙卷风事件的时空分布特征,探讨典型龙卷风个例的环流背景及形成机制。结果表明：1956—2011年黑龙江省龙卷风灾害具有明显的时空分布特征,20世纪60—80年代龙卷风活动频繁,90年代龙卷风发生频次最少,2001—2011年龙卷风发生频次略增加。龙卷风主要集中发生在夏季,以7月发生最多,且多出现在午后至傍晚。对龙卷风空间分析发现黑龙江省绥化地区是龙卷风多发区,与该地区的地理位置、气候条件和大气环流特征有关。不稳定的形势场是龙卷风产生的基础,暖湿气流的输送和冷暖空气的强对流运动为龙卷风的产生提供了有利条件。 相似文献
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综合利用多普勒雷达、地面自动气象站以及风廓线等观测资料和ERA5再分析资料,对2019年7月3日发生于辽宁开原的超级单体风暴伴随EF4级强龙卷环境条件、多普勒雷达回波特征和形成机理进行详细分析。结果表明:本次过程发生于低层暖湿高层冷干强的热力不稳定环境条件下,在地面干线汇合流场形成地面辐合线附近触发湿对流并发展为伴有龙卷的超级单体风暴。龙卷发生于低层钩状回波附近,多普勒雷达上呈现经典超级单体风暴雷达回波特征,低层强的垂直风切变将水平涡度转化为对流风暴中垂直涡度,强上升运动使得顺流涡度倾斜拉伸,从而龙卷发生前17 min在多普勒雷达2.4°仰角首先出现中气旋结构,随后风暴向南移动过程中,风暴的后侧下沉气流(RFD)将中低层的涡度“压低”致使龙卷接地,因此龙卷发生后1 min在0.5°仰角也出现强中气旋并有类龙卷涡旋特征(TVS),中气旋最强时的旋转速度达到28 m·s^(-1)(强中气旋标准),因此本次龙卷符合“自上而下”I型龙卷特征。由于环境干燥空气夹卷造成水滴强烈蒸发和冷却,使得地面出现了1 h降温达10℃的强冷池,过强的冷池可能在促使龙卷消亡过程中起到关键作用,致使龙卷持续了约30 min后消亡。 相似文献
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The synoptic and mesoscale conditions associated with waterspout occurrence in the Adriatic, Ionian and Aegean Sea are examined in an attempt to quantitatively assess the meteorological environment favourable to the development of waterspouts. For this study, synoptic circulation patterns have been examined for 28 waterspout events in the central-eastern Mediterranean. The waterspouts were reported within the summer and fall of 2002, from July to November, a period of unusually high whirlwind activity. The Adriatic was most active during July, August and September and the Ionian and Aegean during September, October and November. Of the examined waterspout cases, 13 out of the total of 28 were found to be fair-weather waterspouts, while 15 represent tornadic events. For waterspout days, the frequency and distribution of four basic synoptic types, namely, south-west flow (SW), long-wave trough (LW), closed low (CLOSED) and short-wave trough (SWT), were investigated. The particular synoptic features that contributed to the development of waterspout activity were examined, based on five selected waterspout case studies. The mesoscale environment was explored using thermodynamic indices, moisture and wind parameters as derived by operational soundings from the nearest sites (preferably upwind) and closest in time to the waterspout occurrences. The results present an analysis of waterspout types in conjunction to thermodynamic and wind parameters for the purpose of determining synoptic patterns and mesoscale conditions most relevant to waterspout occurrences in these sea areas of the Mediterranean. 相似文献
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Miquel Gay 《Atmospheric Research》2007,83(2-4):201-210
Considering the number of dead people, the worst tornado in the last two centuries in Spain is presented. The words used to describe the phenomenon have hidden it to the general public and the specialist The coetaneous press and other printed sources have been revised, and this has let us know the true sense of those words as well as the sequence of the tornadic event.The synoptic situation that was presented by some European Meteorological Offices in 1886 has been revised when all available data and some indirect information have been included.Tornado track and force have been plotted on the actual map of the city following the available information in the newspapers and other documents. Other subjective comments made by the paper writers have allowed us to find out some psychological and sociological aspects used to enhance the tragic perception of their readers. 相似文献
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Tornadoes have occurred in the territory of the Czech Republic throughout history. Although their frequency and intensity are not as high as in the USA, they can cause severe damage as well. That is why a systematic effort to document individual occurrences of this dangerous meteorological phenomenon as far as possible back into the past began in the 1990s. The aim of this investigation is to extend the first European catalogue of tornadoes originally published by Wegener [Wegener A., 1917. Wind-und Wasserhosen in Europe], by the addition of these cases from the Czech Republic.This paper adds further to Setvák, Šálek and Munzar [Setvák M., Šálek M., Munzar J., 2003. Tornadoes within the Czech Republic—from medieval chronicles to the internet society. Atmos. Res. 67–68, 589–605], who reported the earliest documented tornado in the land of the Czech Republic which occurred in AD 1119 in Prague. In so doing, it presents recently discovered tornado cases from the 16th to the early 20th centuries, found in a variety of historical sources since the last ECSS conference held in Prague in 2002. In particular we will focus on the case from Jablonec nad Nisou (northern Bohemia) in 1925, which was probably the first case in the Czech Republic with accompanying photographic documentation of damage caused by a tornado. 相似文献
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Analysis of the Pampa, Texas, multicell storms showed prestorm environmental conditions of a strong horizontal convergence
of moisture, mixing ratio 12 g/kg at the 850 mb level in the Texas Panhandle areas and strong winds with shear veering with
height. Rapid-scan satellite imagery showed that the clouds penetrated above the tropopause and cloud-top temperatures were
at least 4 to 9° C colder than the temperature of the tropopause. This formation and collapsing of high-mass-density overshooting
cloud tops above the tropopause is characteristic of tornadoes in the middle portion of the United States. 相似文献