Large-Eddy Simulation of Sea Breeze at an Idealised Peninsular Site

A high-resolution Large-Eddy Simulation (LES) has been performed to simulate a sea-breeze circulation over an idealized peninsular domain. The simulation is forced with the surface latent/sensible heat fluxes and the large-scale horizontal pressure gradient that are obtained from a mesoscale simulation. This methodology allows the investigation of the physical phenomena that are peculiar for a sea-breeze circulation and that generally require spatial resolution approximately equal to one hundred metres or less. Here, small-scale dynamical effects associated to these phenomena, i.e. the interaction between the sea-breeze front with the convective turbulence generated over-land, the formation of the zero-velocity layer, and the development of the Kelvin-Helmholtz billows, are investigated. Results from the present numerical study have revealed the formation of a zero-velocity layer that is initially near the ground then it rises to define a well-marked sea-breeze depth. Scaling analysis applied to the LES output fields reveals that during the phase of inland penetration the scaling laws for sea-breeze strength and depth have both a proportionality coefficient equal to 0.15.