A Unified Formulation of Quasi‐Geostrophic and Shallow Water Equations via Projection

Abstract This paper introduces a unified model for layered rotating shallow‐water (RSW) and quasi‐geostrophic (QG) equations, based on the intrinsic relationship between these two sets of equations. We propose a novel formulation of the QG equations as a projection of the RSW equations. This formula...

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Main Authors: Louis Thiry, Long Li, Etienne Mémin, Guillaume Roullet
Format: Article
Language:English
Published: American Geophysical Union (AGU) 2024-10-01
Series:Journal of Advances in Modeling Earth Systems
Subjects:
Online Access:https://doi.org/10.1029/2024MS004510
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author Louis Thiry
Long Li
Etienne Mémin
Guillaume Roullet
author_facet Louis Thiry
Long Li
Etienne Mémin
Guillaume Roullet
author_sort Louis Thiry
collection DOAJ
description Abstract This paper introduces a unified model for layered rotating shallow‐water (RSW) and quasi‐geostrophic (QG) equations, based on the intrinsic relationship between these two sets of equations. We propose a novel formulation of the QG equations as a projection of the RSW equations. This formulation uses the same prognostic variables as RSW, namely velocity and layer thickness, thereby restoring the proximity of these two sets of equations. It provides direct access to the ageostrophic velocities embedded within the geostrophic velocities resolved by the QG equations. This approach facilitates the study of differences between QG and RSW using a consistent numerical discretization. We demonstrate the effectiveness of this formulation through examples including vortex shear instability, double‐gyre circulation, and a simplified North Atlantic configuration.
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publishDate 2024-10-01
publisher American Geophysical Union (AGU)
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series Journal of Advances in Modeling Earth Systems
spelling doaj-art-679882e0f1874bb9afa67bdb96075eca2025-08-20T02:12:10ZengAmerican Geophysical Union (AGU)Journal of Advances in Modeling Earth Systems1942-24662024-10-011610n/an/a10.1029/2024MS004510A Unified Formulation of Quasi‐Geostrophic and Shallow Water Equations via ProjectionLouis Thiry0Long Li1Etienne Mémin2Guillaume Roullet3ANGE Team INRIA Paris Laboratoire Jacques‐Louis Lions Sorbonne University Paris FranceODYSSEY Team, INRIA Rennes, IRMAR, University of Rennes I Rennes FranceODYSSEY Team, INRIA Rennes, IRMAR, University of Rennes I Rennes FranceLaboratoire d’Océanographie Physique et Spatiale Université de Bretagne Occidentale Brest FranceAbstract This paper introduces a unified model for layered rotating shallow‐water (RSW) and quasi‐geostrophic (QG) equations, based on the intrinsic relationship between these two sets of equations. We propose a novel formulation of the QG equations as a projection of the RSW equations. This formulation uses the same prognostic variables as RSW, namely velocity and layer thickness, thereby restoring the proximity of these two sets of equations. It provides direct access to the ageostrophic velocities embedded within the geostrophic velocities resolved by the QG equations. This approach facilitates the study of differences between QG and RSW using a consistent numerical discretization. We demonstrate the effectiveness of this formulation through examples including vortex shear instability, double‐gyre circulation, and a simplified North Atlantic configuration.https://doi.org/10.1029/2024MS004510ocean modelsshallow waterquasigeostrophicprojection
spellingShingle Louis Thiry
Long Li
Etienne Mémin
Guillaume Roullet
A Unified Formulation of Quasi‐Geostrophic and Shallow Water Equations via Projection
Journal of Advances in Modeling Earth Systems
ocean models
shallow water
quasigeostrophic
projection
title A Unified Formulation of Quasi‐Geostrophic and Shallow Water Equations via Projection
title_full A Unified Formulation of Quasi‐Geostrophic and Shallow Water Equations via Projection
title_fullStr A Unified Formulation of Quasi‐Geostrophic and Shallow Water Equations via Projection
title_full_unstemmed A Unified Formulation of Quasi‐Geostrophic and Shallow Water Equations via Projection
title_short A Unified Formulation of Quasi‐Geostrophic and Shallow Water Equations via Projection
title_sort unified formulation of quasi geostrophic and shallow water equations via projection
topic ocean models
shallow water
quasigeostrophic
projection
url https://doi.org/10.1029/2024MS004510
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