Nonlinear Averaging in GFD Systems and Higher-Order Balance Dynamics

Thursday, February 14, 2002 - 9:30am - 10:30am
Keller 3-180
Djoko Wirosoetisno (Universiteit Twente)
An averaging (or renormalization) procedure is used to obtain slow evolution equations for all degrees of freedom of a parent model which contains fast and slow dynamics. In a GFD context, the parent model is the primitive equations, the slow dynamics consists of vortical motion and the fast dynamics consists of inertia-gravity waves. This procedure can be carried out (formally) to any order in the timescale separation parameter giving higher-order slow equations.

We will show a close connection between these slow equations and the more familiar classical balance models, which are obtained using a singular perturbation expansion and have a reduced number of degrees of freedom. Issues of convergence of these asymptotic procedures will be considered.