摘要
2014年7月12日浙江省桐乡市一次飑线过境,导致局地出现12级狂风,造成倒房死伤人的重大灾害。通过对大风灾情的实地调查,环境背景场强对流参数和周边杭州、湖州多普勒天气雷达回波特征分析,发现这是一次强中气旋发展伴随局地龙卷风发生的过程,龙卷风发生在飑线弓形回波前沿凸起部分。对本次过程的分析表明,环境场中最佳对流有效位能(BCAPE)和风暴相对螺旋度(SRH)增大、抬升凝结高度低,则出现局地龙卷风的可能性越大。在龙卷风等突发强对流事件的预报中,风廓线产品中西南急流的加强和中心轴下沉、中高层冷空气的契入等,对风暴的触发、雷暴系统的加强有预报提前量。此外,大风重灾发生后,灾区实况及周边多普勒雷达径向速度场资料是判断风灾类型和级别的重要数据资料。
On July 12, 2014, a squall line formed across Tongxiang, Zhejiang. Strong gust winds appeared in Yuanfeng and Jinniu villages and resulted in human casualties and property damage. Through the survey of the disaster, the analysis of environmental conditions and echo characteristics on Hangzhou and Huzhou Doppler weather radars, it is shown that a tornado was produced by a strong cyclonic circulation which had developed associated with the squall line. The strong cyclone occurred in the forefront of the convex portion of bow echo below 1km. The increase of the best convective available potential energy（BCAPE） and storm relative helicity（SRH）, and the decrease of lifting condensation level enhanced the likelihood of tornado. The strengthening and sinking of southwest jet together with the mid- and high-level cold air helped trigger the storm.
出处
《气象科技进展》
2015年第6期13-16,共4页
Advances in Meteorological Science and Technology
