弱垂直风切变下台前飑线不同发展阶段的热力和动力特征分析
投稿时间: 2016-06-02  最后修改时间: 2016-09-12  点此下载全文
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作者单位E-mail
陈耀登 南京信息工程大学 keyu@nuist.edu.cn 
王芳 南京信息工程大学  
章丽娜 中国气象局气象干部培训学院 zhangln@cma.gov.cn 
高梦竹 南京信息工程大学  
牛泽毅 南京信息工程大学  
基金项目:国家科技攻关计划;国家重点基础研究发展计划(973计划)
中文摘要:以2014年7月18日09号超强台风“威马逊”影响期间,发生在湘赣地区的一次台前飑线过程为例,讨论了在垂直风切明显弱于中纬度飑线情况下台前飑线的生成与发展机制。研究表明,在飑线初生阶段,弱垂直切变与较弱冷池相平衡使得飑线直立发展,其前部上干冷下暖湿的不稳定环境条件是其发展加强的热力因素;台风倒槽右侧风向水平切变、飑线前侧的阵锋风是其发展的动力条件。在飑线成熟阶段,飑线后侧的地面冷池范围变大、强度变强导致飑线前方的水汽及能量补给减弱;同时飑线后部中层干冷空气入侵加强,飑线上升气流向冷池方向倾斜,垂直抬升条件减弱,不利于台前飑线的发展维持。成熟阶段这两个特点表明台前飑线由盛转衰。在消散阶段,由于飑线远离台风,台风的影响减弱,导致台前飑线水汽和动力条件不足,从而消亡。
中文关键词:台前飑线  垂直风切变  威马逊  台风
 
The thermal and dynamic characteristics of a Pre-Tropical squall line in different stages under weak vertical shear
Abstract:Take a pre-TC (Tropical Cyclone) squall line process occurred in Hunan and Jiangxi provinces, which effected by the super typhoon “Rammasun” in July 18,2014 for instance, discusses the mechanism of formation and development of this pre-TC squall line when the vertical wind shear was significantly weaker than that of midlatitude. The results showed that, at the爄nitial stage of the pre-TC squall line, the balance between weak vertical shear and weak cold pool lead to the erect updraft at the leading edge of the squall line.. Unstable environmental conditions (cold and dry air overlap warm and moist air) on the front of the squall line is the important thermodynamic factors help to its development and enhancement. The horizontal wind shear on the right side of the typhoon inverted trough and the gust front in the front of squall line are the main dynamical factors of its development. During the mature stage, the cold pool range becomes larger and intensity becomes stronger on the rear side, resulting in reduced moisture and energy supply; at the same time, the middle level cold and dry air invasion strengthened, the updraft tilted toward the cold pool side and the vertical lifting weakened, this is not conducive to the development and maintained of squall line. These two features indicate the decay of the squall line. In the dissipation stage, the squall line move away from the typhoon and the influence of typhoon become weak. Insufficient water vapor supply and lifting lead to the demise of the pre-TC squall line .
keywords:pre-TC squall line, vertical wind shear, Rammasun, Typhoon
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