PROPAGATION OF AN ENVELOPE ROSSBY SOLITON OVER TOPOGRAPHY

By using a simple barotropic model and the multiple-scale perturbation method, a modified nonlinear Schrodinger equation with variable coeff icient, which describes the propagation of a nonlinear Rossby wave pac ket over topography, is derived. With the exception of several specifi c cases the equation is nonintegrable. The behavior of an envelope sol iton traveling toward a topography is studied numerically. It is found that when the initial velocity of the soliton is high, the topography has little effect on it. When the initial velocity is low, the topogr aphic effects on the soliton are significant: The soliton may be refle cted by the topography, or may oscillate around and be captured by the topography, depending on the wave-topography interaction coefficient.