The structure and energetics of transient eddies in a numerical simulation of breaking mountain waves

Abstract

Both the "local convective' and "deep resonant' modes discovered by Laprise and Peltier on the basis of solutions of the nonseparable linear stability problem are clearly identified through these diagnostic analyses. The local convective mode grows from the gravitational potential energy associated with the superadiabatic region (SAR) of the mountain wave and is temporally episodic. The deep resonant mode extracts its energy from the reservoir of kinetic energy associated with the highly deformed mean flow set up by the nonlinear mountain wave and this mode is shown to be responsible for initiating the transition which is accompanied by a rapid acceleration of the low-level flow in the lee of the obstacle. -from Authors