Geostrophic momentum approximation: Difference between revisions

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<div class="definition"><div class="short_definition">The selective approximation of true [[momentum]]  by the corresponding [[geostrophic]] momentum.</div><br/> <div class="paragraph">The approximation is usually made in conjunction with the assumption that the [[Coriolis  parameter]] ''f'' is a constant, in which case it takes the form  <div class="display-formula"><blockquote>[[File:ams2001glos-Ge25.gif|link=|center|ams2001glos-Ge25]]</blockquote></div><div class="display-formula"><blockquote>[[File:ams2001glos-Ge26.gif|link=|center|ams2001glos-Ge26]]</blockquote></div> where ''u'', ''v'', and ''w'' are the eastward, northward, and upward components of the total [[wind]], &#x003c1; is  the [[density]], ''p'' the [[pressure]], and  <div class="display-formula"><blockquote>[[File:ams2001glos-Ge27.gif|link=|center|ams2001glos-Ge27]]</blockquote></div> the eastward and northward components of the [[geostrophic wind]]. In the geostrophic momentum  approximation the geostrophic wind is the advected quantity but the [[advection]] is by the total  (geostrophic plus [[ageostrophic]]) wind. When the geostrophic momentum approximation is combined  with [[geostrophic coordinates]], the resulting equations are termed the [[semigeostrophic  equations]].</div><br/> </div>
<div class="definition"><div class="short_definition">The selective approximation of true [[momentum]]  by the corresponding [[geostrophic]] momentum.</div><br/> <div class="paragraph">The approximation is usually made in conjunction with the assumption that the [[Coriolis parameter|Coriolis  parameter]] ''f'' is a constant, in which case it takes the form  <div class="display-formula"><blockquote>[[File:ams2001glos-Ge25.gif|link=|center|ams2001glos-Ge25]]</blockquote></div><div class="display-formula"><blockquote>[[File:ams2001glos-Ge26.gif|link=|center|ams2001glos-Ge26]]</blockquote></div> where ''u'', ''v'', and ''w'' are the eastward, northward, and upward components of the total [[wind]], &#x003c1; is  the [[density]], ''p'' the [[pressure]], and  <div class="display-formula"><blockquote>[[File:ams2001glos-Ge27.gif|link=|center|ams2001glos-Ge27]]</blockquote></div> the eastward and northward components of the [[geostrophic wind]]. In the geostrophic momentum  approximation the geostrophic wind is the advected quantity but the [[advection]] is by the total  (geostrophic plus [[ageostrophic wind|ageostrophic]]) wind. When the geostrophic momentum approximation is combined  with [[geostrophic coordinates]], the resulting equations are termed the [[semigeostrophic equations|semigeostrophic  equations]].</div><br/> </div>
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Latest revision as of 16:03, 25 April 2012



geostrophic momentum approximation

The selective approximation of true momentum by the corresponding geostrophic momentum.

The approximation is usually made in conjunction with the assumption that the Coriolis parameter f is a constant, in which case it takes the form
ams2001glos-Ge25
ams2001glos-Ge26
where u, v, and w are the eastward, northward, and upward components of the total wind, ρ is the density, p the pressure, and
ams2001glos-Ge27
the eastward and northward components of the geostrophic wind. In the geostrophic momentum approximation the geostrophic wind is the advected quantity but the advection is by the total (geostrophic plus ageostrophic) wind. When the geostrophic momentum approximation is combined with geostrophic coordinates, the resulting equations are termed the semigeostrophic equations.


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