摘要
初步探讨了龙卷生成的动力学因素,其中包含垂直运动的产生、能量的集中和释放以及涡旋的发展。强对流中的强垂直运动取决于对流层中层水平运动的风速,对流层中层大风的出现是强对流发展的信号,也是一种预报指标。同时,大的垂直运动必造成大气中层及其以下的强辐合,因此中层以下的强辐合区也是一个预报积云发展的重要指标。在能量分析过程中最主要的是寻找能量辐合线。如果这条辐合线遇到了较大的垂直运动上升区,会使能量在这条辐合线的垂直运动最大上升区处得以释放,使积云系统进一步发展。在较平坦的地带如果辐合线及能量极值线上出现较大的浮力旋度,则会产生涡旋。这种涡旋又进一步引起速度的变化及垂直运动的形成,促进旋转区垂直运动的加强,形成极小范围的涡旋柱,即出现龙卷。
In this paper, the kinetic factors of tornado formation are discussed, including vertical motion, energy concentration and release, and vortex development. Strong vertical motion in strong convection depends on the horizontal wind velocity in the middle troposphere. The occurrence of strong wind in the middle troposphere is the signal of strong convective development, and is also a prediction index. At the same time, the large vertical motion must causes strong convergence between the middle and low troposphere, so the strong convergence zone below the middle troposphere is also an important index to predict the development of cumulus. In the process of energy analysis, the most important thing is to fnd the energy convergence line. If the convergence line encounters a larger vertical motion, the energy will be released at the regions of the maximum vertical motion of the convergence line, so that the cumulus system will be developed. In relatively fat areas, if there is buoyancy curl in larger convergence line and energy extreme line, the vortex will be produced. This vortex further causesthe formation of horizontal velocity and vertical movement, then it strengthens the vertical movement of the rotational zone, so that vortex column forms, namely the tornado appears.
作者
高守亭
左群杰
杨帅
Gao Shouting;Zuo Qunjie;Yang Shuai(Laboratory of Cloud-Precipitation Physics and Severe Storms （LACS）, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029;University of Chinese Academy of Sciences, Beijing 100049)
出处
《气象科技进展》
2018年第2期24-27,35,共5页
Advances in Meteorological Science and Technology
基金
国家自然科学基金重大研究计划(91437215)
国家自然科学基金项目(41575047
41575064)
关键词
龙卷
动力
涡旋
tornado, dynamics, vortex
