On the Application of Baroclinic Instability and Sensible Heat Exchange to Explain Blocking Ridge Development

Abstract

It has recently been suggested that exchange of sensible heat with the underlying surface is necessary for the baroclinic instability of waves on the scale of observed blocking ridge activity over the North Pacific. Theoretical support for this idea comes from studies of baroclinic instability in a two-layer model with diabatic heating proportional to the wave temperature. In this paper the problem is treated in a continuously stratified model. It is shown that such diabatic heating is not needed for instability at long wavelengths and that when it is present the growth rate of unstable modes is decreased.