Roughness Length

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Roughness length (z₀) is a parameter which is a measure of terrain roughness as "seen by" surface wind. It is formally the height (in meters) at which the wind speed becomes zero when the logarithmic wind profile above the roughness sub-layer is extrapolated to zero wind speed. In fact, the roughness length lies within the roughness sub-layer, where the wind speed deviates from the logarithmic wind profile. This parameter represents the bulk effect of roughness elements in the surface layer and very approximately has a value of around 0.1 times the height of the roughness elements.

[edit] See also

• Monin-Obukhov length
• Wind profile power law
• Log wind profile