Effect of Orography on Deep Convection Initiation Produced by Two Sea-Breeze Fronts

In this study, large-eddy simulations (LESs) of converging sea breezes over a peninsula are performed to investigate the effect of its orography on the ability of the model to simulate an observed event of deep convection initiation and, more generally, to understand deep convection in a regime in which both sea-breeze and mountain–plain circulations play a role. The present idealized experiments indicate that the inclusion of orography in the simulation, while of modest height (200 m), dramatically changes the simulations and allows deep convection to develop before the collision of the two sea-breeze fronts at the peninsula center. Using LES, the present study explores in detail the interaction among the sea breezes, the mountain–plain circulation, and deep convection as a function of the slope of the hill. It is found that the timing, mechanisms, and structure of convective cells are extremely sensitive to the hill slope.