Lowest Atmospheric Layer

Lowest Atmospheric Layer 

a region of the atmospheric boundary layer. The lowest atmospheric layer extends from the earth’s surface up to a height of several tens of meters and is the atmospheric layer most subject to the earth’s surface effects. Its extent varies within fairly broad limits, depending on the atmosphere’s thermal stratification, on wind velocity, and on the unevenness of the earth’s surface. Meteorological elements in the lowest atmospheric layer change radically with increasing height: vertical gradients of wind velocity, of temperature, and of humidity are tens and hundreds of times greater than corresponding quantities in higher layers, but the absolute magnitude of these gradients decreases with increasing height. Wind velocity increases with height, but the wind’s direction remains almost unchanged. The upper limit of the lowest atmospheric layer often coincides with the upper limit of temperature inversion and of fog and urban or industrial pollution of the atmosphere.