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| {{technical|date=January 2012}}
| | Nice to satisfy you, my title is Numbers Held although I don't truly like being called like that. Doing ceramics is what my family members and I appreciate. He utilized to be unemployed but now he is a meter reader. California is where I've usually been residing and I adore every working day living here.<br><br>Also visit my website [http://www.ninfeta.tv/blog/66912 www.ninfeta.tv] |
| The [http://amsglossary.allenpress.com/glossary/search?id=obukhov-length1 Obukhov length] is used to describe the effects of buoyancy on turbulent flows, particularly in the lower tenth of the [[atmospheric boundary layer]]. It was first defined by [[Alexander Obukhov]]<ref>{{cite book|last=Jacobson|first=Mark Z.|title=Fundamentals of Atmospheric Modeling|url=http://books.google.co.in/books?id=WPwEf-1f73wC&printsec=frontcover&source=gbs_ge_summary_r&cad=0#v=onepage&q&f=false|edition=2|year=2005|publisher=[[Cambridge University Press]]}}</ref> in 1946,.<ref>{{cite journal |last1=Obukhov |first1=A.M.|year=1946|title=Turbulence in an atmosphere with a non- uniform temperature.|journal= Tr. Inst. Teor. Geofiz. Akad. Nauk. SSSR|volume=1|pages=95–115}}</ref><ref>{{cite journal |last1=Obukhov |first1=A.M.|year=1971|title=Turbulence in an atmosphere with a non-uniform temperature (English Translation)| journal=Boundary-Layer Meteorology|volume=2| pages=7–29|bibcode = 1971BoLMe...2....7O |doi = 10.1007/BF00718085 }}</ref> It is also known as the Monin–Obukhov length because of its important role in the similarity theory developed by [[Andrei Monin|Monin]] and Obukhov.<ref>{{cite journal |last1=Monin|first1=A.S.|last2=Obukhov |first2=A.M.|year=1954|title=Basic laws of turbulent mixing in the surface layer of the atmosphere.|journal= Tr. Akad. Nauk SSSR Geofiz. Inst|volume=24|pages=163–187}}</ref>
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| The '''Obukhov length''' is defined by
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| :<math> | |
| L = - \frac{u^3_*\bar\theta_v}{kg(\overline {w^'\theta^'_v})_s}\
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| </math>
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| where <math>u_*</math> is the [[Friction velocity|frictional velocity]], <math>\bar\theta_v</math> is the mean virtual [[potential temperature]], <math>(\overline{w^'\theta^'_v})_s</math> is the surface virtual potential temperature flux, k is the [[von Kármán constant]]. The virtual potential temperature flux is given by
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| :<math>
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| \overline {w^'\theta^'_v}=\overline {w^'\theta^'}+0.61\overline{T}\; \overline {w^'q^'}
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| </math>
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| where <math>\theta</math> is potential temperature, <math>\overline{T}</math> is absolute temperature and <math>q</math> is specific humidity.
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| By this definition, <math>L</math> is usually negative in the daytime since <math>\overline {w^'\theta^'_v}</math> is typically positive during the daytime over land, positive at night when <math>\overline {w^'\theta^'_v}</math> is typically negative, and becomes infinite at dawn and dusk when <math>\overline {w^'\theta^'_v}</math> passes through zero.
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| A physical interpretation of <math>L</math> is given by the Monin–Obukhov similarity theory. During the day <math>-L</math> it is the height at which the buoyant production of [[turbulence kinetic energy]] (TKE) is equal to that produced by the shearing action of the wind (shear production of TKE).
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| ==References==
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| {{Reflist}}
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| {{DEFAULTSORT:Monin-Obukhov length}}
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| [[Category:Atmospheric dispersion modeling]]
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| [[Category:Boundary layer meteorology]]
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| [[Category:Fluid dynamics]]
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| [[Category:Buoyancy]]
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| {{Climate-stub}}
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Latest revision as of 11:14, 3 June 2014
Nice to satisfy you, my title is Numbers Held although I don't truly like being called like that. Doing ceramics is what my family members and I appreciate. He utilized to be unemployed but now he is a meter reader. California is where I've usually been residing and I adore every working day living here.
Also visit my website www.ninfeta.tv