Local Winds

winds in limited areas that are distinguished by their velocity, recurrence, direction, or other characteristics.

Winds of various origins are subsumed under this general term: (1) Local circulations that are independent of general circulation in the atmosphere and are associated with special features of heating of the earth’s surface—breezes in coastal regions of seas and large lakes and mountain-valley winds in the mountains, which change direction twice a day; and glacial winds, which blow continuously downward along the slopes of glacial valleys. (2) Winds associated with currents of the general atmospheric circulation that pass over mountain massifs. On the leeward slopes of the mountains, the air current acquires a descending velocity component and is intensified; a wind of the foehn, bora, sarma, or similar type. Such winds lead to characteristic changes in the general weather pattern (warming and decreasing humidity with the foehn, cooling with the bora, and so on). (3) Winds associated with currents of the general atmospheric circulation but lacking a descending component, though topographically intensified in a particular region—for example, the afganets and Ursat’evskaia winds of Middle Asia, the canyon wind of North America, and the kosava on the Balkan Peninsula. (4) Winds associated with currents of the general atmospheric circulation not even intensified in that particular region but creating in it special weather conditions that are important in practical terms and that bring either warming or cooling, blowing sand or humidity, severe snowstorms, and so on—the sukhovei (dry wind) of the southern part of the European USSR, the sirocco in the Mediterranean, the khamsin in Egypt, the kharmattan in West Africa, the purga in Northern and Central Asia, the blizzard in North America, the pampero in Argentina, and others. (5) The numerous dust devils, squalls, dust storms, sandstorms, and such associated with unstable stratification in the atmosphere when there is intense heating of the air from below or an influx of cold air in the upper layers. The names of local winds are extremely numerous and most often indicate their predominant direction or the geographic region in which they are observed.