The vortical response to penetrative convection and the associated gravity-wave generation

Abstract

This study documents the vortical motions that arise due to penetrative convective updraughts. Using an idealized axisymmetric model of dry thermals it is shown that in a stable environment the baroclinic generation of vorticity forms a circulation that opposes updraught overshoot and manifests the first signature of gravity waves emanating from the thermal. Continued baroclinic generation of vorticity of oscillating sign completes the first full wavelength and populates the wave packet. These examples provide an alternate description of the generation of gravity waves by penetrative convection and provide further insight into the morphology of the wave source. © 2008 Royal Meteorological Society.