ON THE DEVELOPMENT OF SYNOPTIC-SCALE DISTURBANCES OVER THE SUBTROPICAL OCEANS

Abstract

Disturbances with scales of a few thousand kilometers are commonly observed in the troposphere over the subtropical oceans. Synoptic experience seems to indicate that many of these large-scale disturbances are driven by latent heat released in organized convection. To explore this possibility, a series of numerical experiments were conducted with a simple, two-layer, quasi-geostrophic model. The convective heating function was treated in the same manner as that employed by various investigators in recent studies of hurricane dynamics. In this formulation, convection is controlled by frictional convergence in the Ekman layer. These numerical experiments show that this heating mechanism, within the framework of the simple dynamical model employed, can produce significant intensification of large-scale disturbances.