Atmospheric boundary layer: Difference between revisions

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(Abbreviated ABL; <br/>''also called'' boundary layer, planetary boundary  layer.) The bottom layer of the [[troposphere]] that is in contact with the surface of the earth.<br/> It is often turbulent and is capped by a [[static stability|statically stable]] layer of air or [[temperature inversion]].  The ABL depth (i.e., the [[inversion]] height) is variable in time and space, ranging from tens of  meters in strongly statically stable situations, to several kilometers in convective conditions over  deserts. During [[fair]] weather over land, the ABL has a marked [[diurnal]] cycle. During daytime, a  [[mixed layer]] of vigorous [[turbulence]] grows in depth, capped by a statically stable [[entrainment zone|entrainment  zone]] of intermittent turbulence. Near [[sunset]], turbulence decays, leaving a [[residual layer]] in place  of the mixed layer. During nighttime, the bottom of the residual layer is transformed into a statically  [[stable boundary layer]] by contact with the radiatively cooled surface. [[cumulus|Cumulus]] and [[stratocumulus]]  clouds can form within the top portion of a humid ABL, while [[fog]] can form at the bottom of a  stable boundary layer. The bottom 10% of the ABL is called the [[surface layer]]. <br/>''Compare'' [[Ekman layer|Ekman  layer]].<br/> Stull, R. B. 1988. An Introduction to Boundary Layer Meteorology.  666 pp.  
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== atmospheric boundary layer ==
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<div class="definition"><div class="short_definition">(Abbreviated ABL; <br/>''also called'' boundary layer, planetary boundary  layer.) The bottom layer of the [[troposphere]] that is in contact with the surface of the earth.</div><br/> <div class="paragraph">It is often turbulent and is capped by a [[static stability|statically stable]] layer of air or [[temperature inversion]].  The ABL depth (i.e., the [[inversion]] height) is variable in time and space, ranging from tens of  meters in strongly statically stable situations, to several kilometers in convective conditions over  deserts. During [[fair]] weather over land, the ABL has a marked [[diurnal]] cycle. During daytime, a  [[mixed layer]] of vigorous [[turbulence]] grows in depth, capped by a statically stable [[entrainment zone|entrainment  zone]] of intermittent turbulence. Near [[sunset]], turbulence decays, leaving a [[residual layer]] in place  of the mixed layer. During nighttime, the bottom of the residual layer is transformed into a statically  [[stable boundary layer]] by contact with the radiatively cooled surface. [[cumulus|Cumulus]] and [[stratocumulus]]  clouds can form within the top portion of a humid ABL, while [[fog]] can form at the bottom of a  stable boundary layer. The bottom 10% of the ABL is called the [[surface layer]]. <br/>''Compare'' [[Ekman layer|Ekman  layer]].</div><br/> </div><div class="reference">Stull, R. B. 1988. An Introduction to Boundary Layer Meteorology.  666 pp. </div><br/>
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Revision as of 16:37, 7 November 2023

(Abbreviated ABL;
also called boundary layer, planetary boundary layer.) The bottom layer of the troposphere that is in contact with the surface of the earth.
It is often turbulent and is capped by a statically stable layer of air or temperature inversion. The ABL depth (i.e., the inversion height) is variable in time and space, ranging from tens of meters in strongly statically stable situations, to several kilometers in convective conditions over deserts. During fair weather over land, the ABL has a marked diurnal cycle. During daytime, a mixed layer of vigorous turbulence grows in depth, capped by a statically stable entrainment zone of intermittent turbulence. Near sunset, turbulence decays, leaving a residual layer in place of the mixed layer. During nighttime, the bottom of the residual layer is transformed into a statically stable boundary layer by contact with the radiatively cooled surface. Cumulus and stratocumulus clouds can form within the top portion of a humid ABL, while fog can form at the bottom of a stable boundary layer. The bottom 10% of the ABL is called the surface layer.
Compare Ekman layer.
Stull, R. B. 1988. An Introduction to Boundary Layer Meteorology. 666 pp.


Abbreviation for atmospheric boundary layer.

  1. The layer of fluid near a boundary that is affected by friction against that boundary surface, and possibly by transport of heat and other variables across that surface.
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