Perturbation Pressure and Cumulus Convection

Abstract

A simple model of perturbation pressure in cumulus convection is presented. The results show that the buoyancy- and drag-induced perturbation pressures act against the prescribed forcing. The dynamic pressure is found to be a consequence of the Bernoulli effect and a balance for the centrifugal force which arises from the curved motion of the air. Quantitative calculations reveal that the pressure force is of the same order of magnitude as the buoyancy and drag and offers a plausible explanation for the acceleration of negatively buoyant air near the base of convective updrafts.