Atmospheric Boundary Layer


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atmospheric boundary layer

[¦at·mə¦sfir·ik ′bau̇n·drē ‚lā·ər]
(meteorology)

Atmospheric Boundary Layer

 

(or friction layer, planetary boundary layer), the air layer adjacent to the earth’s surface. Because of the intense turbulent mixing that occurs in it, its properties are determined primarily by the thermal and dynamic influence of the underlying surface. The thickness of the layer ranges from 300—400 m to 1-2 km. The greater the roughness of the underlying surface and the more intense the turbulence, the greater the thickness. For this reason, the thickness increases with increasing wind speed and decreasing thermal stability of the atmosphere. Transfer of heat and moisture between the earth’s surface and the free atmosphere lying above the layer is accomplished through the layer. The layer is characterized by an especially high level of contamination by dust and condensation products. Up to an altitude of 100 m wind speed within the layer increases approximately in proportion to the logarithm of the altitude; above 100 m it increases more and more slowly.

REFERENCE

Laikhtman, D. L. Fizika pogranichnogo sloia atmosfery, 2nd ed. Leningrad, 1970.
References in periodicals archive ?
The aim of the investigation is to evaluate the effect of meteorological conditions and product loading indicator on the change of VOCs concentration in lower atmospheric boundary layer during different seasons in the territories adjacent to the oil terminals.
Such environmental prevention measures would make those companies that pollute air, give thorough attention to the issue and search for technological solutions for the reduction of VOCs emission to the lower atmospheric boundary layer.
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Statistical data processing have revealed that the number and nature of loading operations (loading indicator) carried out in oil terminals determines VOCs concentration in the lower atmospheric boundary layer only in those cases, when the loading indicator is higher than 80% (P < 0.
After making an analysis of VOCs concentration investigation results obtained during different seasons and of the multifactor dispersion analysis with 95% reliability, it has been determined that the change of VOCs concentration in the lower atmospheric boundary layer depends on wind speed when it is higher than 4 m/s (at 10 m height, P < 0.
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