Barotropic model: Difference between revisions
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|Meaning=#Any of a number of [[model atmospheres]] in which some of the following conditions exist throughout the motion: coincidence of [[pressure]] and [[temperature]] surfaces; absence of [[vertical wind shear]]; absence of vertical motions; absence of horizontal [[velocity divergence]]; and conservation of the vertical component of [[absolute vorticity]]. | |||
|Explanation=Barotropic models are usually divided into two classes: the nondivergent barotropic model and the divergent barotropic model (also called the shallow-water equations).<br/> | |||
#A single-parameter, single-level [[atmospheric model]] based solely on the [[advection]] of the initial [[circulation]] field.<br/> The simplest form of barotropic model is based on the [[barotropic]] vorticity advection equation: <blockquote>[[File:ams2001glos-Be3.gif|link=|center|ams2001glos-Be3]]</blockquote> where ψ is the geostrophic [[streamfunction]], '''V'''<sub>ψ</sub> is the nondivergent [[wind]], and ''f'' is the [[Coriolis parameter|Coriolis parameter]]. The equation is derived by assuming that a vertical portion of the [[atmosphere]] is barotropic (i.e., [[density]] is constant on [[pressure]] surfaces) and nondivergent. Because there are no vertical variations or [[thermal]] advection processes in a barotropic model, it cannot predict the development of new weather systems. | |||
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Latest revision as of 13:19, 26 March 2024
- Any of a number of model atmospheres in which some of the following conditions exist throughout the motion: coincidence of pressure and temperature surfaces; absence of vertical wind shear; absence of vertical motions; absence of horizontal velocity divergence; and conservation of the vertical component of absolute vorticity.
Barotropic models are usually divided into two classes: the nondivergent barotropic model and the divergent barotropic model (also called the shallow-water equations).
- A single-parameter, single-level atmospheric model based solely on the advection of the initial circulation field.
The simplest form of barotropic model is based on the barotropic vorticity advection equation:
where ψ is the geostrophic streamfunction, Vψ is the nondivergent wind, and f is the Coriolis parameter. The equation is derived by assuming that a vertical portion of the atmosphere is barotropic (i.e., density is constant on pressure surfaces) and nondivergent. Because there are no vertical variations or thermal advection processes in a barotropic model, it cannot predict the development of new weather systems.
