Atmospheric Boundary Layer

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atmospheric boundary layer

[¦at·mə¦sfir·ik ′bau̇n·drē ‚lā·ər]

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.


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.
The pollution of the lower atmospheric boundary layer with VOCs is especially recorded in those regions of the western Lithuania, wherein the oil processing industry and oil production fields are developed, and where there is a concentration of oil and oil products' terminals.
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.
Pollutant dispersion modeling around buildings with CFD is not straightforward, even for the simplest situation: the steady release of a non-buoyant, non-reactive gas in the vicinity of an isolated building model in a neutral atmospheric boundary layer.
2007b), "CFD evaluation of the wind speed conditions in passages between buildings - effect of wall-function roughness modifications on the atmospheric boundary layer flow", J.
The consistent simulation of horizontally homogeneous atmospheric boundary layers in computational domains (Richards and Hoxey 1993, Blocken et al.
The fluid motion along a discontinuous wall develops a flow which leads to a mean velocity profile and a turbulence level capable to assure the atmospheric boundary layer dynamic characteristic simulation conditions in the test section of the tunnel.
Regarding the turbulent structure of the flow, the turbulent intensities are described by a classical distribution, which is characteristic for the atmospheric boundary layer.
The experimental research revealed that for different type of terrain roughness, the atmospheric boundary layer can be modeled with very good results regarding the mean velocity profile as well as the turbulent structure using the wind tunnel with discontinuity.

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