山区干环境下弱降水超级单体龙卷事件研究  

Analysis of lowprecipitation supercell-induced tornado event under ambient dry conditions in a mountainous region

作　　者：王宏[1,2,3] 王秀明 王万筠[5] 赵岩 裴宇杰 胡赛安 冯钰博 杨域 姜旭 WANG Hong;WANG Xiuming;WANG Wanjun;ZHAO Yan;PEI Yujie;HU Saian;FENG Yubo;YANG Yu;JIANG Xu(CMA Xiong’an Atmospheric Boundary Layer Key Laboratory,Xiong’an 071800,China;Key Laboratory of Meteorology and Ecological Environment of Hebei Province,Shijiazhuang 050021,China;Chengde Meteorological Observatory,Chengde 067000,China;China Meteorological Administration Training Centre,Beijing 100081,China;Binhai New District Meteorological Observatory,Tianjin 300457,China;Hebei Provincial Meteorological Observatory,Shijiazhuang 050021,China)

机构地区：[1]中国气象局雄安大气边界层重点开放实验室,雄安新区071800 [2]河北省气象与生态环境重点实验室,石家庄050021 [3]河北省承德市气象局,承德067000 [4]中国气象局气象干部培训学院,北京100081 [5]天津市滨海新区气象局,天津300457 [6]河北省气象台,石家庄050021

出　　处：《气象学报》2025年第2期193-208,共16页Acta Meteorologica Sinica

基　　金：国家重点研发计划课题(2022YFC3004104);中国气象局重点创新团队(CMA2022ZD07);河北省气象局灾害性天气机理研究创新团队、承德市基础研究项目(202305B074)。

摘　　要：为增强对山区龙卷风暴的认识,应用不同波段天气雷达和风廓线等探测资料,分析了2023年5月14日发生在华北北部山区(围场和隆化)的2个EF1级弱龙卷,包括近风暴环境和风暴精细结构。结果表明:龙卷发生在500 hPa冷涡后部西北气流背景下,龙卷母风暴由干线及其伴随的地面辐合线触发。近风暴环境对流有效位能和0—6 km风垂直切变较强,低层水汽和0—1 km风垂直切变显著增大有利于超级单体龙卷形成。午后热雷暴活动对山区局地水汽影响是此次龙卷近风暴环境水汽含量升高的主要影响因素。产生龙卷的超级单体风暴回波强度总体不强,其中围场龙卷风暴回波强度在40 dBz以下,且强回波范围小,地面降水不足2 mm,中气旋和钩状回波头部对应旋转上升气流与降水回波分离,2个龙卷风暴均为弱降水超级单体风暴。分析了2个弱降水超级单体风暴的近风暴环境及精细结构演变,识别出低层中等强度中气旋和龙卷涡旋特征(TVS),表明X波段雷达可捕捉到弱降水超级单体龙卷。围场龙卷特征的出现与龙卷发生有很好的时间对应关系,隆化龙卷发生前8 min可观测到TVS特征,此次弱降水超级单体龙卷预警时效较短。An analysis of two EF1 weak tornadoes that occurred in Weichang and Longhua including the pre-storm environmental conditions and fine structures is conducted based on observations of radars on different bands and wind profile radars.The results show that the tornado occurred under the background of northwesterly flows behind a 500 hPa cold vortex,and the tornadic supercells were triggered by the dryline and its associated surface convergence.The supercell tornadoes occurred in the pre-storm environment with strong convective available potential energy(CAPE)and 0—6 km vertical wind shear,while water vapor at the low level and 0—1 km vertical wind shear significantly increased.The thunderstorm activity in the afternoon improved low-level moisture.The reflectivity of these two tornadic supercells was overall less intense with that of the Weichang tornado less than 40 dBz.The area was small and the precipitation near the tornado was less than 2 mm.The rotating updraft corresponding to the mesocyclone and the hook echo head were separated from the precipitation echo.Both of these two tornadic storms exhibited low-precipitation(LP)supercell characteristics.In this paper,the pre-storm environment and structural evolution of the two LP supercell storms are recorded.Moderate mesocyclone at low levels and tornadic vortex signatures(TVS)were identified,indicating the X-band radar can capture the LP supercell tornado. The occurrence of the TVS corresponded well with the occurrence of the Weichang tornado, and the Longhua TVS was detected 8 min in advance, indicating that the leading time for the LP supercell tornado warning was limit.

关 键 词：龙卷 干环境 超级单体 弱降水 山区 

分 类 号：P458.2[天文地球—大气科学及气象学]