纯斜压基流上斜压波的发展和锋生过程

DEVELOPMENT OF BAROCLINIC WAVES IN PURE BAROCLINIC FLOWS AND FRONTOGENESIS

关键词:  斜压波  锋生  三维半地转方程

Key words:  Baroclinic wave  Frontogenesis  Three-dimensional semigeostrophic model

摘要:

利用地转动量近似和水平坐标变换建立的三维半地转方程,讨论了具有均匀位涡的基态流上非线性斜压扰动的发展和锋面的形成过程。计算结果表明,对于纯斜压流,斜压波的发展既取决于初始扰动,也与基流的垂直切变有关,垂直切变越大,斜压波增长越快。不同的基流.扰动有不同的增长率。对于某个确定的基流,斜压波在各个时刻的特性仅取决于初始扰动。斜压扰动发展到一定程度,形成大的风速和等温线密集区,即产生锋。

Abstract:

The developing process of nonlinear baroclinic disturbances and the formation of fronts in pure basic baroclinic currents with uniform potential vorticity are discussed by using a three-dimensional semigeostrophic model. The results show that the development of waves depends on both the initial disturbances and on the vertical shear of the flow, the growth of waves increases with increasing vertical shear. The growth rate of waves is different for the different flow, and for a given flow. the behaviour of waves is determined by the initial disturbances. With developing waves, the great wind speed and temperature gradient occur, and the fronts are formed.