Ventilating Warm Rings: Theory and Energetics

Abstract

Observations suggest that heat loss to the atmosphere causes an important modification of the density structure of warm core rings. In this study, f-plane models of rings under a cooling atmosphere are examined in order to provide a dynamic framework for the interpretation of ring observations and to assess ring effects on their environment. Two-layer models with finite upper-layer volumes are examined The idealizations in these models include zero potential vorticity in the ring and an initially motionless lower layer. In the simplest problem, the atmosphere is assumed to completely remove the heat anomaly of the ring through cooling. The results of this calculation place limits on the restructuring of warm rings that can be forced by heat exchange. The time-dependent ventilation problem is also examined by considering the effects of partial heat withdrawals and cold air outbreaks. Estimates of energy release by rings during adjustment are large, suggesting the flux of significant energy into the internal wave bands by a single cooling event.