By the use of the WKBJ method combined with the characteristic line method, the asymptotic solution of a gravity wave envelope in the atmosphere of horizontal heterogeneous stratification and time-varying stratificati...By the use of the WKBJ method combined with the characteristic line method, the asymptotic solution of a gravity wave envelope in the atmosphere of horizontal heterogeneous stratification and time-varying stratification is obtained. The solution shows that not only the variation of amplitude of the gravity wave but also the variation of wavelength and the width of the envelope are affected by the horizontal heterogeneity. As the wave envelope moves from a region, of strong stratification to a weak one, the horizontal wavelength will become shorter, the width of the envelope will narrow and its amplitude will increase. The variation of stratification with time cannot lead to the variation of wavelength and envelope width, but the amplitude of the wave envelope will increase while the amplitude of the wave decreases in time.展开更多
Starting from the anelastic equations describing deep convection in cylindrical coordinates, the WKBJ method is used to discuss the stability of asymmetric three-dimensional inhomogeneous vortex under the conditions o...Starting from the anelastic equations describing deep convection in cylindrical coordinates, the WKBJ method is used to discuss the stability of asymmetric three-dimensional inhomogeneous vortex under the conditions of nonhydrostatic and non-equilibrium gradient wind. From the equation of wave action, the devel-opment of disturbance is qualitatively analyzed.展开更多
The development of symmetric disturbance superposed on the background field of Hoskins- Bretherton (1972) frontogenesis model is investigated by means of WKBJ approach,It is found that the forcing of large-scale defor...The development of symmetric disturbance superposed on the background field of Hoskins- Bretherton (1972) frontogenesis model is investigated by means of WKBJ approach,It is found that the forcing of large-scale deformation,the frontal circulation and the spatial-temporal variations of stability parameters (F^2,N^2,M^2) can bring about the development of symmetric disturbance, even though the frontal baroclinic flow is symmetric stable (F^2N^2-M^2=q>0),The frontogenetical process of deformation confluence zone and the ascending branch of frontal circulation are in favor of the development of symmetric disturbance,The actions of ageostrophic shear in frontal zone and the variation of stability parameters are dependent on the structure of disturbance.展开更多
Effects of topography on the propagation and development of inertia gravity waves are investigated by means of WKBJ method.The equation of wave action conservation is obtained.It is found that the inertia gravity wave...Effects of topography on the propagation and development of inertia gravity waves are investigated by means of WKBJ method.The equation of wave action conservation is obtained.It is found that the inertia gravity wave tends to propagate to the higher elevation area,meanwhile the amplitudes of the waves increase.While the inertia gravity waves propagate to a lower elevation area, their amplitudes decrease.展开更多
There is a common hypothesis for the presently popular mild-slope equations that wave particle motion is irrotational. In this paper, an attempt is made to abandon the irrotational assumption and to set up new sea wav...There is a common hypothesis for the presently popular mild-slope equations that wave particle motion is irrotational. In this paper, an attempt is made to abandon the irrotational assumption and to set up new sea wave packet equations on slowly varying topography by use of the WKBJ method. To simplify the deduction, the two-dimensional shallow water equations are used to describe the sea wave particle motion in the very shallow nearshore area. The established equations can give some characteristics of wave propagation near shore.展开更多
基金This study was Supported by the National Special Key Project Fund(No.G1998040907).
文摘By the use of the WKBJ method combined with the characteristic line method, the asymptotic solution of a gravity wave envelope in the atmosphere of horizontal heterogeneous stratification and time-varying stratification is obtained. The solution shows that not only the variation of amplitude of the gravity wave but also the variation of wavelength and the width of the envelope are affected by the horizontal heterogeneity. As the wave envelope moves from a region, of strong stratification to a weak one, the horizontal wavelength will become shorter, the width of the envelope will narrow and its amplitude will increase. The variation of stratification with time cannot lead to the variation of wavelength and envelope width, but the amplitude of the wave envelope will increase while the amplitude of the wave decreases in time.
文摘Starting from the anelastic equations describing deep convection in cylindrical coordinates, the WKBJ method is used to discuss the stability of asymmetric three-dimensional inhomogeneous vortex under the conditions of nonhydrostatic and non-equilibrium gradient wind. From the equation of wave action, the devel-opment of disturbance is qualitatively analyzed.
基金It is supported by the National Natural Science Foundation of China.
文摘The development of symmetric disturbance superposed on the background field of Hoskins- Bretherton (1972) frontogenesis model is investigated by means of WKBJ approach,It is found that the forcing of large-scale deformation,the frontal circulation and the spatial-temporal variations of stability parameters (F^2,N^2,M^2) can bring about the development of symmetric disturbance, even though the frontal baroclinic flow is symmetric stable (F^2N^2-M^2=q>0),The frontogenetical process of deformation confluence zone and the ascending branch of frontal circulation are in favor of the development of symmetric disturbance,The actions of ageostrophic shear in frontal zone and the variation of stability parameters are dependent on the structure of disturbance.
文摘Effects of topography on the propagation and development of inertia gravity waves are investigated by means of WKBJ method.The equation of wave action conservation is obtained.It is found that the inertia gravity wave tends to propagate to the higher elevation area,meanwhile the amplitudes of the waves increase.While the inertia gravity waves propagate to a lower elevation area, their amplitudes decrease.
基金This work was supported by the National Outstanding Youth Foundation of China (Grant No. 49825161) the Foundation for Graduate Students of East China Normal University the Opening Fund of the State Key Labora-tory of Estuarine and Coastal Research.
文摘There is a common hypothesis for the presently popular mild-slope equations that wave particle motion is irrotational. In this paper, an attempt is made to abandon the irrotational assumption and to set up new sea wave packet equations on slowly varying topography by use of the WKBJ method. To simplify the deduction, the two-dimensional shallow water equations are used to describe the sea wave particle motion in the very shallow nearshore area. The established equations can give some characteristics of wave propagation near shore.
