Spatial and Time Structure of a Gravity Wave in Horizontal Atmosphere of Heterogeneous Stratification

By the use of the WKBJ method combined with the characteristic line method, the asymptotic solutionof a gravity wave envelope in the atmosphere of horizontal heterogeneous stratification and time-varyingstratification is obtained. The solution shows that not only the variation of amplitude of the gravitywave but also the variation of wavelength and the width of the envelope are affected by the horizontalheterogeneity. As the wave envelope moves from a region of strong stratification to a weak one, thehorizontal wavelength will become shorter, the width of the envelope will narrow and its amplitude willincrease. The variation of stratification with time cannot lead to the variation of wavelength and envelopewidth, but the amplitude of the wave envelope will increase while the amplitude of the wave decreases in time.