Winter High Pressure - Mater of mixing air in the Belluno Pre-alpine basin

摘要

During winter, High pressures can be present for several days on the Alps with problem of mixing air in the valleys, especially in the Pre-alpine basin like Belluno depression. Normally in this area winds are often very weak, especially during winter, when air viscosity (member of Reynolds) increases appreciably and laminar and stratify flow tends to deposit and almost immovable, without micro-turbulences, so when winds are strong on top of mountains, including in certain situation of Foehn. The absence or long periods of calm of wind without any exchange and strong stagnation of the same air mass in the lower level generate serious problems on the air quality due to high concentration in pollutants (pm10)