A generalization of Ertel's potential vorticity to a cloudy, precipitating atmosphere

This paper discusses the generalization of Ertel's PV to a cloudy, precipitating atmosphere. The recommended generalization is P = ρ-1ζ ˙ ∇θρ, where ρ is the total density of moist air, ζ is the absolute vorticity, and θρ is the virtual potential temperature. Associated with this form are three...

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Main Author: Wayne Schubert
Format: Article
Language:English
Published: Borntraeger 2004-12-01
Series:Meteorologische Zeitschrift
Online Access:http://dx.doi.org/10.1127/0941-2948/2004/0013-0465
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author Wayne Schubert
author_facet Wayne Schubert
author_sort Wayne Schubert
collection DOAJ
description This paper discusses the generalization of Ertel's PV to a cloudy, precipitating atmosphere. The recommended generalization is P = ρ-1ζ ˙ ∇θρ, where ρ is the total density of moist air, ζ is the absolute vorticity, and θρ is the virtual potential temperature. Associated with this form are three important properties: (1) the solenoidal term is annihilated (i.e., ∇θρ˙ (∇ρ × ∇p) = 0, where p is the total pressure, the sum of the partial pressures of dry air and water vapor); (2) the limiting form for a dry atmosphere is the classical Ertel PV; (3) P is invertible, i.e., it carries all the necessary dynamical information about the balanced wind and mass fields. Two other possible generalizations are discussed,ρ-1ζ ˙∇θe and ρ-1ζ ˙∇θ*e, where θe is the equivalent potential temperature and θ*e is the saturation equivalent potential temperature. The former is rejected because properties (1) and (3) are lost, while the latter is rejected because property (2) is lost.
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spelling doaj.art-8ba61548536247f5ba384142e80086fc2024-02-08T08:44:37ZengBorntraegerMeteorologische Zeitschrift0941-29482004-12-0113646547110.1127/0941-2948/2004/0013-046553382A generalization of Ertel's potential vorticity to a cloudy, precipitating atmosphereWayne SchubertThis paper discusses the generalization of Ertel's PV to a cloudy, precipitating atmosphere. The recommended generalization is P = ρ-1ζ ˙ ∇θρ, where ρ is the total density of moist air, ζ is the absolute vorticity, and θρ is the virtual potential temperature. Associated with this form are three important properties: (1) the solenoidal term is annihilated (i.e., ∇θρ˙ (∇ρ × ∇p) = 0, where p is the total pressure, the sum of the partial pressures of dry air and water vapor); (2) the limiting form for a dry atmosphere is the classical Ertel PV; (3) P is invertible, i.e., it carries all the necessary dynamical information about the balanced wind and mass fields. Two other possible generalizations are discussed,ρ-1ζ ˙∇θe and ρ-1ζ ˙∇θ*e, where θe is the equivalent potential temperature and θ*e is the saturation equivalent potential temperature. The former is rejected because properties (1) and (3) are lost, while the latter is rejected because property (2) is lost.http://dx.doi.org/10.1127/0941-2948/2004/0013-0465
spellingShingle Wayne Schubert
A generalization of Ertel's potential vorticity to a cloudy, precipitating atmosphere
Meteorologische Zeitschrift
title A generalization of Ertel's potential vorticity to a cloudy, precipitating atmosphere
title_full A generalization of Ertel's potential vorticity to a cloudy, precipitating atmosphere
title_fullStr A generalization of Ertel's potential vorticity to a cloudy, precipitating atmosphere
title_full_unstemmed A generalization of Ertel's potential vorticity to a cloudy, precipitating atmosphere
title_short A generalization of Ertel's potential vorticity to a cloudy, precipitating atmosphere
title_sort generalization of ertel s potential vorticity to a cloudy precipitating atmosphere
url http://dx.doi.org/10.1127/0941-2948/2004/0013-0465
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