| Abstract: | In this paper, the nonlinear Kelvin wave equations with "positive-only" nonlinear (conditional) heatingat the equator are reduced to a sixth order nonlinear ordinary differential equation by using the Galerkinspectral truncated method. The stability analysis indicates that when the heating parameter increases, thesupercritical pitchfork and Hopf bifurcations can occur for the prescribed three heating profiles. Numericalcalculations are made with the help of the fourth order Rung-Kutta method. It is found that the convection heating related Hop f bifurcation can lead to limit cycle and chaotic solutions. In a wide range of heating parameter, the solutions possess 30-60-day periods, and are dominated by wavenumbers one and two,especially by wavenumber one. In addition, the zonal winds of the low-frequency solutions have a phasereversal between the upper and lower tropospheres. Thus, it appears that the convection heating relatedHopf bifurcation might be a possible mechanism of 30-60-day oscillation in the tropical atmosphere. |
