一次龙卷天气过程中小尺度特征分析  

Analysis of Mesoscale and Microscale Characteristics of a Tornado Process

作　　者：李云艳[1] 郑艳[1] 杨仁勇[1] 

机构地区：[1]海南省气象台,海南海口570203

出　　处：《农业灾害研究》2014年第5期34-37,40,共5页Journal of Agricultural Catastrophology

基　　金：公益性行业(气象)科研专项(GYHY201406009);中国气象局预报员专项(CMAYBY2013-053)

摘　　要：2008年5月29日16:30—16:40在海南省海口市三江镇附近出现的龙卷天气,海口多普勒天气雷达建成后首次探测到龙卷,由超级单体引发,强度达到F2级。分析表明,南支槽东移和中低层华南切变线的维持为龙卷产生提供了有利的天气背景条件;龙卷运动路径与地面中尺度辐合线位置基本吻合;钩状回波与东北移动的飑线合并演变成为S型对流风暴,龙卷发生在S型对流风暴强烈的前、后侧入流的切变最大处;这次龙卷过程在海口多普勒雷达径向速度图上呈现为明显的中气旋和中层深厚辐合区特征,可以提前3个体扫(18 min)对龙卷预警;龙卷涡旋附近谱宽值较大,谱宽大值区伸展高度与中气旋伸展高度相当(3km以上);中气旋M和TVS图形产品对龙卷天气的指示性十分明显,发现TVS报警应立即发布龙卷或灾害性大风预警。The torado occurred at 16： 30 -16：40 on May 29, 2008 near the Sanjiang Town, Haikou City is the first one that detected by Haikou Doppler weather radar. It was a F2 level supercell tornado caused by non-tropical cyclone system. The results indicated that a south branch trough passed through easterly and low level wind shear line existed for a long time in the South Chi- na gave a favorable weather background condition for tornado-genesis. The passage of tornado was in line with the mesoscale convergence line of surface wind. The hook echo and squall line moved northeasterly merged and then developed to an S type convective storm. The tornado occurred at the biggest shear between the forward and backward inflow of S type convective storm. On the radical velocity map of Doppler radar, this tornado matched along with a mesocyclone and deep convergence which made it possible to release a tornado early warning prior to 18 minutes （three Volume Coverage Pattern （VCP） time）. The values of spectrum width near the tornado vortex were bigger and this big spectrum width area extended up to same height of mesocyclone （3 km and above）. M and TVS products are significant for tornado forecast. An early warning of tornado or disastrous gust should be released as soon as TVS warning alarm.

关 键 词：龙卷 中气旋 中层深厚辐合区 多普勒雷达 

分 类 号：P458.3[天文地球—大气科学及气象学]