摘要
By using two-dimensional dynamical equations in x-z plane with Boussinesq approximation,the effects of the second-order vertical shear of the basic flow ■ and the horizontal gradient of temperature (M) on the gravity wave and the isolated gravity wave are discussed.The magnitudes of ■ and M corresponding to the linear and nonlinear stabilities of the gravity waves are worked out,respectively.The results show that amplitude and width of the isolated gravity wave are closely related to ■ and M.It is indicated that the isolated gravity wave with a width of about 10 km can be motivated by the disturbance of sub-synoptic scale in the certain ranges of flow field shear and temperature gra- dient,while the motivated waves may be associated with the cold surge ahead of a cold front and the other mesoscale synoptic systems.
By using two-dimensional dynamical equations in x-z plane with Boussinesq approximation,the effects of the second-order vertical shear of the basic flow ■ and the horizontal gradient of temperature (M) on the gravity wave and the isolated gravity wave are discussed.The magnitudes of ■ and M corresponding to the linear and nonlinear stabilities of the gravity waves are worked out,respectively.The results show that amplitude and width of the isolated gravity wave are closely related to ■ and M.It is indicated that the isolated gravity wave with a width of about 10 km can be motivated by the disturbance of sub-synoptic scale in the certain ranges of flow field shear and temperature gra- dient,while the motivated waves may be associated with the cold surge ahead of a cold front and the other mesoscale synoptic systems.
