Izaña

The Izaña Atmospheric Observatory is located on the island of Tenerife, Spain, roughly 300 km west of the African coast. The observatory is situated on a mountain plateau at 2372.90 m above sea level, 15 km north-east of the volcano Teide (3718 m a.s.l.). The local wind regime at the site is dominated by north-westerly winds. Clean air and clear sky conditions generally prevail throughout the year. The station is normally above a temperature inversion layer, generally well established over the island, and below the descending branch of the Hadley cell. The ground in the vicinity around Izaña is loosely covered with light volcanic soil. The vegetation in the surrounding area is sparse, consisting mainly of broom. A belt of pine forest grows between 1000 and 2000 meters a.s.l. The population in Tenerife is distributed over the coastal platform. During nighttime downslope (catabatic) wind produces the arrival of free troposphere air to Izaña. During daytime, small amounts of air coming from the forest can arrive to the station due to surface upslope wind produced by ground diurnal heating. Apart from this effect, there is no arrival of polluted air from the rest of the island, due to the presence of a strong subtropical temperature inversion layer.