二维单个涡旋的动力学分析  

Dynamic Analysis of 2-Dimension Single Vortex

作　　者：刘刚 唐民 高洁 刘式达[4] 

机构地区：[1]民航江西空中交通管理分局,江西南昌330114 [2]民航华东空中交通管理局气象处,上海200335 [3]民航西北空中交通管理局气象中心,陕西西安710082 [4]北京大学物理学院大气科学系,北京100871

出　　处：《气象与减灾研究》2008年第4期8-12,共5页Meteorology and Disaster Reduction Research

基　　金：国家自然基金重点项目(编号:90511009).

摘　　要：通过对大气流场在奇点处作速度场分解,确定雅可比矩阵特征值与大气运动形式之间的关系,以分析二维气旋、反气旋流场的特性,进一步了解实际二维大气的单个涡旋形态的动力学特性和形成机制。研究认为,任意水平速度场均可分解为线性的含有涡度场(与反对称矩阵对应)和变形场(与对称矩阵对应)的形式。高层地转平衡的高(低)压系统,奇点附近只有负(正)涡度场而无变形场,在天气图上表现为只有顺(逆)时针旋转的闭合涡旋。低层考虑摩擦的高(低)压系统,奇点附近不仅有负(正)涡度场,还有变形场。也就是说,在北半球高压不仅有顺时针旋转气流,还有向外的辐散气流;低压不仅有逆时针旋转气流,还有辐合气流。In this paper, by decomposing velocity field on the singular point of flow field and analyzing the characters of 2- Demention cyclone and anti-cyclone, the relationship between Jacobi matrix and atmospheric motion pattern is studied to understand the dynamics and mechanism of single vortex in real 2-demention atmosphere. The results show that any horizontal velocity field can be decomposed into linear forms, which include the vorticity （corresponding to skew matrix） and the distortion （corresponding to symmetrical matrix）. There is only negative （positive） vorticity but not distortion near the singular point at high- level geostrophic equilibrium high （low） pressure, which presents clockwise （anticlockwise） closed-circulation in synoptic chart. If the friction is considered, there are not only negative （positive） vorticity but also distortion near the singular point at low-level high （low） pressure, which means that for the northern hemispheric high pressure there is clockwise as well as anticlockwise vortex, and for the low pressure there are both anticlockwise vortex and convergent flow.

关 键 词：大气涡旋 速度场分解 奇点 特征值. 

分 类 号：P401[天文地球—大气物理学与大气环境]