The Evolution of a Nonlinear Rossby Wave Critical Level: Effects of Viscosity

Abstract

The time-dependent nonlinear Rossby wave equation is solved numerically in order to study the evolution of a forced wave on a parallel flow in the presence of a critical level. Inviscid and viscous integrations are performed, the latter yielding steady-state solutions in the critical layer as well as away from it. These solutions are shown to be in excellent agreement with Haberman's (1972), obtained from a similar steady-state equation. The implications for planetary-wave propagation and/or structure studies are further discussed.