A regional implementation of a mixed finite-element, semi-implicit dynamical core

Fuente: arXiv
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Autori principali: Johnson, Christine, Shipway, Ben, Melvin, Thomas, Bendall, Thomas, Kent, James, Boutle, Ian, Brown, Alex, Zerroukat, Mohamed, Buchenau, Benjamin, Wood, Nigel
Natura: Preprint
Pubblicazione: 2025
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author Johnson, Christine
Shipway, Ben
Melvin, Thomas
Bendall, Thomas
Kent, James
Boutle, Ian
Brown, Alex
Zerroukat, Mohamed
Buchenau, Benjamin
Wood, Nigel
author_facet Johnson, Christine
Shipway, Ben
Melvin, Thomas
Bendall, Thomas
Kent, James
Boutle, Ian
Brown, Alex
Zerroukat, Mohamed
Buchenau, Benjamin
Wood, Nigel
contents This paper explores how to adapt a new dynamical core to enable its use in one-way nested regional weather and climate models, where lateral boundary conditions (LBCs) are provided by a lower-resolution driving model. The dynamical core has recently been developed by the Met Office and uses an iterated-semi-implicit time discretisation and mixed finite-element spatial discretisation. The essential part of the adaptation is the addition of the LBCs to the right-hand-side of the linear system which solves for pressure and momentum simultaneously. The impacts on the associated Helmholtz preconditioner and multigrid techniques are also described. The regional version of the dynamical core is validated through big-brother experiments based on idealised dynamical core tests. These experiments demonstrate that the subdomain results are consistent with those from the full domain, confirming the correct application of LBCs. Inconsistencies arise in cases where the LBCs are not perfect, but it is shown that the application of blending can be used to overcome these problems.
format Preprint
id arxiv_https___arxiv_org_abs_2503_11528
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle A regional implementation of a mixed finite-element, semi-implicit dynamical core
Johnson, Christine
Shipway, Ben
Melvin, Thomas
Bendall, Thomas
Kent, James
Boutle, Ian
Brown, Alex
Zerroukat, Mohamed
Buchenau, Benjamin
Wood, Nigel
Fluid Dynamics
Numerical Analysis
This paper explores how to adapt a new dynamical core to enable its use in one-way nested regional weather and climate models, where lateral boundary conditions (LBCs) are provided by a lower-resolution driving model. The dynamical core has recently been developed by the Met Office and uses an iterated-semi-implicit time discretisation and mixed finite-element spatial discretisation. The essential part of the adaptation is the addition of the LBCs to the right-hand-side of the linear system which solves for pressure and momentum simultaneously. The impacts on the associated Helmholtz preconditioner and multigrid techniques are also described. The regional version of the dynamical core is validated through big-brother experiments based on idealised dynamical core tests. These experiments demonstrate that the subdomain results are consistent with those from the full domain, confirming the correct application of LBCs. Inconsistencies arise in cases where the LBCs are not perfect, but it is shown that the application of blending can be used to overcome these problems.
title A regional implementation of a mixed finite-element, semi-implicit dynamical core
topic Fluid Dynamics
Numerical Analysis
url https://arxiv.org/abs/2503.11528