Numerical Simulation of Sea Breeze Convergence over Antarctic Peninsula

Abstract

The convergence zone induced by sea breeze systems over Antarctic Peninsula is analyzed for the summer season of 2013–2015. 59 days, selected by satellite images for the absence of major synoptic forcing, are simulated using the WRF model. Sea breeze convergence has been detected in 21 of these days, mostly during evening hours and under large-scale winds. Breeze events are associated with a cold anomaly at the peninsula with respect to the climatology. This condition favors the onset of the necessary horizontal thermal gradients to trigger the breeze circulation. At the same time, no anomaly of the average pressure at sea level is found, indicating that events are favored when the average synoptic flow is present. Case studies indicate that the convergence location over the peninsula is controlled by the synoptic wind. An average convergence over the peninsula happens from 14:00 to 22:30 UTC, with a maximum at 18:00 UTC. There is a strong potential temperature gradient between the surface of the peninsula and the sea, with the sea breeze circulation system extending up to 1.2 km or higher. The sensible heat flux reaches 80 W/m2 at the top of mountains and 10 W/m2 near the coast.