| 1522强台风“彩虹”螺旋雨带中衍生龙卷的超级单体演变与机理研究Ⅱ:回波结构和钩状回波形成机理 |
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| 引用本文： | 王炳赟,魏鸣,范广洲,杜爱军.1522强台风“彩虹”螺旋雨带中衍生龙卷的超级单体演变与机理研究Ⅱ:回波结构和钩状回波形成机理[J].热带气象学报,2018,34(4):481-488. |
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| 作者姓名： | 王炳赟 魏鸣 范广洲 杜爱军 |
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| 作者单位： | 1.南京信息工程大学/气候与气象灾害协同创新中心，江苏 南京 210044 |
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| 基金项目： | 国家自然科学基金项目41675029国家自然科学基金项目91644226国家自然科学基金项目91537214国家自然科学基金项目41405063国家自然科学基金项目41705008国家重点基础研究发展计划973项目2013CB430102国家重点研发计划“全球变化及应对”重点专项2016YFA0602004地理信息科学教育部重点实验室开放研究基金资助项目KLGIS2015A01中国气象科学研究院灾害天气国家重点实验室开放课题2016LASW-B12江苏省普通高校研究生科研创新计划项目KYZZ-0246重庆市气象局青年基金项目QNJJ-201710 |
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| 摘 要： | 为深入研究超级单体的结构演变及其相关机理，对1522“彩虹”台风登陆前后外围雨带中衍生龙卷的超级单体进行了深入分析。研究结果表明，该台风雨带内衍生龙卷的超级单体持续约1.5 h左右，生命史较短。3个超级单体都在回波段的尾部发展，其中汕尾和佛山2个超级单体在发展过程中合并其后部相对较弱的单体。涡旋结构位于超级单体回波穹隆和悬挂回波附近，龙卷发生期间呈“涡管”状，向移动方向倾斜。由Bernoulli原理和空气动力学相关知识可知，超级单体某一高度上阻碍气旋(反气旋)向前运动的空气阻力f和周围压力差δF的共同作用合力F是钩状回波形成的原因。由此提出的钩状回波概念模型可合理解释北半球西风带和东风带内超级单体演变过程中钩状回波的形成结构及其机理，有助于进一步丰富超级单体结构及其理论内涵，加深对此类强天气致灾机理的理解。
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| 关 键 词： | 台风 超级单体 钩状回波 涡旋 Bernoulli 流体力学 |
| 收稿时间： | 2017-07-21 |
THE EVOLUTION AND MECHANISM OF THE TORNADIC SUPERCELLS IN THE OUTER RAINBANDS OF STRONG TYPHOON MUJIGAE (1522). PART Ⅱ: EVOLUTION OF STRUCTURE AND MECHANISM OF HOOK ECHO |
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| Abstract: | Based on conventional observation data of China, Doppler radar data and reanalysis data of ECWMF, the evolution and mechanism of supercells that induced tornadoes in the outer rainbands were analyzed during the landing of "Mujigae", and this is the second part about the evolution of reflectivity structure and mechanism of hook echo. The supercells generally sustained approximately 1.5 h in the rainbands of the typhoon, with a short lifetime. The duration of reflectivity above 50 dBz of a supercell in Shanwei matched a moderately-lived severe storm event that lasted approximately 2.5 hours, while two supercells in Guangzhou were for long-lived severe storm events that lasted approximately 5 hours. The three supercells induced tornadoes at the end of the echo they belonged to. The supercells in Shanwei and Foshan absorbed and combined weak storms nearby during their growing processes. The rotation was near a domed echo and a hanging echo in the supercell phase, and showed obviously "vortex tube" shape tilted toward the moving direction. Bernoulli's principle can explain the formation mechanism of hook echo in supercells, and could be used reasonably in the formation process of the hook echo in the supercell in westerlies or easterlies in the Northern Hemisphere. The evolution and mechanism of supercells would be helpful in further understanding the causes for severe weather processes. |
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