NONLINEAR ROSSBY WAVES AND THEIR INTERACTIONS .1. COLLISION OF ENVELOPE SOLITARY ROSSBY WAVES

By using the multiple-scale perturbation method a set of equations whi ch describes two interacting nonlinear Rossby waves in the barotropic atmosphere is derived. The equations are used to study the collision o f two envelope solitary Rossby waves. It is found that for a range of parameters, the collision interactions are envelope soliton-like in th at the properties of the two envelope solitary waves change very littl e. For other parameters, new ''inelastic'' effects are observed, inclu ding speed changes, fission of envelope solitary waves and energy disp ersion. It is also found that despite of the complexity of the interac ting process, the energy of each wave is conserved.