摘要
β近似下,在等压面上的锋区可变换成孤立子.因此,为了了解锋面形成和维持的动力机制,本文从锋面方程组出发,设基态流场定常,利用地转动量假定及在平衡态附近按Taylor级数展开的方法,最后导出KdV方程。通过讨论,我们得出,锋面是由于非线性过程与频散过程共同作用并达到平衡而形成的,其中形变场对锋面形成是至关重要的.在线性情况下形成不了锋面.锋面移速与锋区强度、基态流场及非绝热加热等有关,而等压面上锋区宽度与锋面强度、切变场等有关,与形变场无直接关系.斜压性对锋面形成是必须的,而凝结加热也具有重要的辅助作用.
By β-approximation, the frontal zone on an isobaric chart can be changed into a soliton. In order to study the mechanism of frontognesis and frontal maintenance, the frictionless equations are utilized with the hypothesis that the basic flow field is independent of time. We finally get a frontal KdV equation of the semi-geostrophic flow using the method to expand the nonlinear term near the equilibrium into the Taylor series. It can be concluded that the genesis of front results from the reaction and equilibrium between nonlinear process and dispersional course, and that the deformation field is the key factor to it. Under linear conditions frontal genesis is impossible. The velocity of a front is related to the frontal intensity, the deformation field, and the diabatic heat etc..; and the width of the front with the intensity and shearing field, and it has not direct relation with deformation flow. Baroclinicity is necessary to frontogenesis and the maintenance of fronts.
出处
《大气科学》
CSCD
北大核心
1993年第4期424-433,共10页
Chinese Journal of Atmospheric Sciences
基金
"长江中下游连阴连晴天气研究"课题
国家气象局"高原基金"
关键词
锋
KDV方程
孤立子
切变场
锋生
Front
KdV- equation
Soliton
Deformation field
Shearing field.
