台风“摩羯”螺旋雨带中衍生龙卷的非超级单体特征  

Non-supercell Characteristics of Tornadoes Derived from Spiral Rain Belt of the Typhoon ‘YAGI’

作　　者：朱义青 王庆华 ZHU Yiqing;WANG Qinghua(Linyi Meteorological Bureau of Shandong Province,Linyi 276004,Shandong,China)

机构地区：[1]山东省临沂市气象局,山东临沂276004

出　　处：《干旱气象》2020年第2期263-270,共8页Journal of Arid Meteorology

基　　金：国家自然科学基金项目(41375120);中国气象局预报员专项(CMAYBY2017-042);山东省气象局专项(SDYBY2019-14、2018sdqxm17)共同资助。

摘　　要：2018年8月14日受台风"摩羯"外围螺旋雨带影响,山东遭受7个龙卷风,其中影响惠民县姜楼镇的非超级单体龙卷达F2级致灾标准。利用常规观测资料、卫星云图、探空资料及多普勒雷达资料等,对此次强龙卷过程单体特征进行诊断分析。结果表明:龙卷发生在台风"摩羯"外围螺旋雨带中,其发生地位于台风中心35°方向约160 km处,为湿度梯度大值和TBB梯度大值相重合区域内。大尺度环流背景和低空急流、较低的抬升凝结高度及较大的低层风垂直切变均利于龙卷的发生。初始阶段小尺度涡旋先在近地面层出现,随后向上发展加强,并自高层减弱消失,且最大反射率因子强中心高度的快速下降和跃升过程对应地面龙卷的出现和消失;龙卷发生前7 min在0.5°仰角径向速度上出现小尺度涡旋,表明龙卷接地或即将发生,小尺度涡旋顶高明显上升可作为龙卷迅速增强的指标。Seven tornadoes attacked in Shandong on 14 August 2018 under the effect of spiral rain belt around the typhoon ‘YAGI’, and the non-supercell tornado affected Jianglou Town of Huimin County was up to disaster-inducing standard with F2 level. Based on conventional observation data, satellite cloud images, radiosonde data and Doppler radar data, the non-supercell characteristics during the strong tornado process were analyzed. The results show that the tornado occurred in spiral rain belt around the typhoon ‘YAGI’, and it was about 160 km from the center of the typhoon with 35° direction, in which the gradient of humidity and TBB were large. The large-scale circulation backgroud, low-level jet stream, lower lift-up condensation level(LCL) and larger vertical wind shear in low level were conducive to the occurrence of tornado. The small-scale vortex at the initial stage appeared near surface layer first, then it developed upward and strengthened, while the weakening and disappearance was from upper level to low level, and the rapid declining and jump rising process of strong central height of the maximum reflectivity factor was well corresponded to the emergence and disappearance of ground tornado. The small-scale vortex occurred on 0.5° elevation of radar radial speed 7 minutes before the tornado occurred, which indicated that the tornado was grounding or imminent. The apparent rise of small-scale vortex top height can be used as an indicator of the rapid enhancement of tornado.

关 键 词：非超级单体龙卷 卫星云图特征 雷达回波特征 龙卷涡旋特征(TVS) 

分 类 号：P458[天文地球—大气科学及气象学]