Local closure: Difference between revisions

Latest revision as of 05:53, 29 March 2024

A method of approximating the effects of turbulence at some height z_k that considers only the meteorological state in the immediate vicinity of that height.

For example, if estimating a turbulent flux at z_k, one need consider only the meteorological state (wind speed, wind shear, wind curvature, temperature gradient, etc.) at z_k. The same approach works for higher-order turbulence statistics at z_k, which can be estimated from values and gradients of lower-order statistics. Local closure implicitly assumes that turbulence consists of only small eddies, and thus it has difficulty approximating those flows where large eddies are important, such as for thermals in the convective boundary layer. Nonetheless, local closures are easier to use than nonlocal closures.

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+{{Term
+|Display title=local closure
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+|Definitions={{Definition
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+|Num=1
+|Meaning=A method of approximating the effects of [[turbulence]] at some height ''z''<sub>''k''</sub> that considers  only the meteorological state in the immediate vicinity of that height.
-<div class="termentry">
+|Explanation=For example, if estimating a [[turbulent flux]] at ''z''<sub>''k''</sub>, one need consider only the meteorological  state ([[wind speed]], [[wind shear]], [[wind]] curvature, [[temperature]] gradient, etc.) at ''z''<sub>''k''</sub>. The same  approach works for higher-order turbulence statistics at ''z''<sub>''k''</sub>, which can be estimated from values  and gradients of lower-order [[statistics]]. Local closure implicitly assumes that turbulence consists  of only small [[eddies]], and thus it has difficulty approximating those flows where large eddies are  important, such as for [[thermals]] in the [[convective boundary layer]]. Nonetheless, local closures  are easier to use than [[nonlocal closures]].
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+}}
-== local closure ==
+}}
-  </div>
-<div class="definition"><div class="short_definition">A method of approximating the effects of [[turbulence]] at some height ''z''<sub>''k''</sub> that considers  only the meteorological state in the immediate vicinity of that height.</div><br/> <div class="paragraph">For example, if estimating a [[turbulent flux]] at ''z''<sub>''k''</sub>, one need consider only the meteorological  state ([[wind speed]], [[wind shear]], [[wind]] curvature, [[temperature]] gradient, etc.) at ''z''<sub>''k''</sub>. The same  approach works for higher-order turbulence statistics at ''z''<sub>''k''</sub>, which can be estimated from values  and gradients of lower-order [[statistics]]. Local closure implicitly assumes that turbulence consists  of only small [[eddies]], and thus it has difficulty approximating those flows where large eddies are  important, such as for [[thermals]] in the [[convective boundary layer]]. Nonetheless, local closures  are easier to use than [[nonlocal closures]].</div><br/> </div>
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