A Two-Dimensional Numerical Investigation of the interaction between Sea Breezes and Deep Convection over the Florida Peninsula

Abstract

Deep convection initiated by sea breezes over the Florida peninsula is simulated using a two-dimensional nonhydrostatic model. Reasonable agreement is obtained between model results and observations for the three types of undisturbed days classified by Blanchard and López. The convergence of the east and west coast sea breezes is the primary control on the timing and location of rapid convective development, and this is mainly determined by the low-level winds. The simulated convection is spatially concentrated and does not produce an extensive stratiform region. Sensitivity tests are performed for a variety of wind and thermodynamic profiles, and for different soil moisture contents. During the early stages of these simulations, small convective cells develop in between the sea-breeze fronts. As the outer cells at the sea-breeze fronts deepen these smaller cells are suppressed. Typically, during the midafternoon a new cell explosively develops in between the sea-breeze fronts and the outer cells usually decay, although merger occasionally occurs. The decay of convection, subsequent to this rapid development, can generate very deep horizontally propagating gravity waves. A considerable amount of the convective available potential energy released, and associated subsidence warming is carried away from the convective region by these deep gravity-wave modes having a horizontal propagation speed much larger than the ambient winds. Model output is analyzed to examine the precipitation patterns, heat and moisture budgets, radiational heating and momentum transports.