Sea Breeze in Summer, Along the West Coast of Portugal

Along the west coast of Portugal, in a narrow strip of 20 to 35 Km, more than 70% of the portuguese population is concentrated, and more than 90% of air pollutants in Portugal are released in this region. The atmospheric circulations detailed study as well as the thermal structure in the lower troposphere are very important because they are determinant factors in the air pollutants transport and dispersion conditions. During the dry period, since middle May to middle October, it is frequent the formation of a thermal low pressure over the central region of the Iberian peninsula; in association with this low pressure, a persistent ridge over the north of the peninsula is connected with the Azores anticiclone. Under these conditions, along the west coast of Portugal, especially during the months since June to September, the sea breeze regime is a direct consequence of the differential heating of the surface air, which reaches more than 20 oC between the land and the sea, in the horizontal scale along the coastal strip.