Surface roughness: Difference between revisions
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<div class="definition"><div class="short_definition">The geometric characteristic of a surface associated with its efficiency as a [[momentum]] sink for [[turbulent flow]], due to the generation of [[drag]] forces and increased [[vertical wind shear]].</div><br/> <div class="paragraph">In [[micrometeorology]], the surface roughness is usually measured by the [[roughness length]], a length [[scale]] that arises as an integration constant in the derivation of the [[logarithmic wind profile]] relation. In [[neutral stability]] the logarithmic wind profile extrapolates to zero [[wind]] velocity at a height equal to the surface roughness length. Several formulas exist to parameterize this length scale as a function of the roughness element geometry (e.g., spacing and silhouette area). Tabulated values for various surface types are published in most micrometeorological texts. <br/>''See'' [[momentum flux]], [[zero-plane displacement]].</div><br/> </div><div class="reference">Stull, R. B. 1988. An Introduction to Boundary Layer Meteorology. 666 pp. </div><br/> | <div class="definition"><div class="short_definition">The geometric characteristic of a surface associated with its efficiency as a [[momentum]] sink for [[turbulent flow]], due to the generation of [[drag]] forces and increased [[vertical wind shear|vertical wind shear]].</div><br/> <div class="paragraph">In [[micrometeorology]], the surface roughness is usually measured by the [[roughness length]], a length [[scale]] that arises as an integration constant in the derivation of the [[logarithmic velocity profile|logarithmic wind profile]] relation. In [[neutral stability]] the logarithmic wind profile extrapolates to zero [[wind]] velocity at a height equal to the surface roughness length. Several formulas exist to parameterize this length scale as a function of the roughness element geometry (e.g., spacing and silhouette area). Tabulated values for various surface types are published in most micrometeorological texts. <br/>''See'' [[momentum flux|momentum flux]], [[zero-plane displacement]].</div><br/> </div><div class="reference">Stull, R. B. 1988. An Introduction to Boundary Layer Meteorology. 666 pp. </div><br/> | ||
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Latest revision as of 17:02, 25 April 2012
surface roughness
The geometric characteristic of a surface associated with its efficiency as a momentum sink for turbulent flow, due to the generation of drag forces and increased vertical wind shear.
In micrometeorology, the surface roughness is usually measured by the roughness length, a length scale that arises as an integration constant in the derivation of the logarithmic wind profile relation. In neutral stability the logarithmic wind profile extrapolates to zero wind velocity at a height equal to the surface roughness length. Several formulas exist to parameterize this length scale as a function of the roughness element geometry (e.g., spacing and silhouette area). Tabulated values for various surface types are published in most micrometeorological texts.
See momentum flux, zero-plane displacement.
See momentum flux, zero-plane displacement.
Stull, R. B. 1988. An Introduction to Boundary Layer Meteorology. 666 pp.
