Autan (wind)

The Autan is a wind blowing in south-west France (in the Languedoc and Roussillon regions ) from the Mediterranean Sea from the south-east. The name is derived from the Latin altus (dt. High ), with altanus as "the one waving from the high (sea)".

The Autan blows from the Mediterranean coast between Narbonne and Perpignan inland to Toulouse and sometimes weakened to Agen , as well as over the plateaus of the southern Périgord and through the central Dordogne valley . In these areas it has long been used to power numerous windmills. Usually the wind is dry, warm and turbulent, with an average speed of 30 to 40 km / h; in peaks over 100 km / h can be reached.

The Autan arises from the interplay of two events: When there is a large, south-westerly air current over the Iberian Peninsula, the wind builds up on the Pyrenees . On the one hand, air masses flow east around the Pyrenees into the depression between Narbonne and Toulouse. On the other hand, foehn forms along the Pyrenees , which further increases the wind speed on the north side. There the Autan is wedged between the Pyrenees and Montagne Noire and reaches the highest speeds at Revel due to the Venturi effect .

With opposite pressure differences between the Pyrenees and the Mediterranean, a strong northwest wind , the Tramontane, can develop .

Web links

• Tramontane and Autan , Vigilance Météo (de) - Forecast chart for the Autan