INFLUENCES OF TOPOGRAPHY ON BAROCLINIC SOLITARY ROSSBY WAVES IN A MULTILEVEL MODEL

The KdV equation with topography included in an N-level model is derived. It is shown that if the topography ex- ists. the KdV equation may describe the solitary Rossby waves in the case of basic current without vertical shear, and it is no necessary to introduce the MKdV equation. The results of calculations show that the change of horizontal shear pattern of basic flow may cause an important change of the streamline pattern of the solitary waves with the odd meridional wavenumber m, and has no effect for the even meridional wavenumber m. The vertical shear increases the steepness of the barotropic solitary modes, and it has a complicated effect on the baroclinic modes. The influences of topographic slope on the solitary waves are very great. The southern and northern slopes of topography may cause dif- ferent solitary wave patterns, with the effect of northern slope greater. The effect of Froude number on the solitary waves is generally to steepen the solitary waves, however, the effect also depends on the meridional wavenumber m and the modes of solitary wave.