Shear excitation of atmospheric gravity waves. Part II: nonlinear radiation from a free shear layer.

Abstract

This paper addresses the efficiency and characteristics of two mechanisms that have been proposed to account for the excitation of radiating gravity waves by Kelvin-Helmholtz (KH) instabilities at a free shear layer in a stratified atmosphere. These mechanisms are the vortex pairing or subharmonic interaction observed to occur at the interface between two homogeneous fluid layers and the KH interaction of 'envelope radiation' mechanism found to occur in the presence of propagating unstable modes.-from Author