An observation of hot air downwelling over Pantelleria Island in the Strait of Sicily

During a period of strong SW winds, a local anomalous hot air mass was observed at sea level on the lee side of Pantelleria Island in the Strait of Sicily. The hot air, some 10 °C above ambient, was produced by downward transport or mixing from an intense inversion layer occurring above 500 m. This rapidly moving layer, associated with a flow from the Libyan Desert, was apparently perturbed by the 836-m high volcanic cone of the island. Laboratory models suggest that such an interaction could produce phenomena, i.e., vortex shedding and lee waves, all of which would mix or advect the upper warm air downward. This, together with the adiabatic heating effect, would produce the hot air phenomena.