Diabatic sources of potential vorticity in the general circulation

Abstract

A form of the potential vorticity (PV) budget is proposed that facilitates analysis on the role of global heat sources and sinks in the general circulation. A local diabatic source of PV occurs due to vertical variations of heating. Additionally, since the irrotational mass circulation in isentropic coordinates is uniquely linked to diabatic heating, the associated horizonatal avection of PV may be viewed as a diabatic source. The sum of these processes constitutes an effective "baroclinic wave source' due to diabatic processes, and is analogous to the effective barotropic Rossby wave source due to divergence as discussed by Sardeshmukh and Hoskins. -from Author