A Kinematic Kinetic Energy Backscatter Parametrization: From Implementation to Global Ocean Simulations
Abstract Ocean models at eddy‐permitting resolution are generally overdissipative, damping the intensity of the mesoscale eddy field. To reduce overdissipation, we propose a simplified, kinematic energy backscatter parametrization built into the viscosity operator in conjunction with a new flow‐depe...
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ftdoajarticles:oai:doaj.org/article:cf765c74416b485482fcceeb2f3717e0 2023-05-15T18:18:40+02:00 A Kinematic Kinetic Energy Backscatter Parametrization: From Implementation to Global Ocean Simulations S. Juricke S. Danilov N. Koldunov M. Oliver D. V. Sein D. Sidorenko Q. Wang 2020-12-01T00:00:00Z https://doi.org/10.1029/2020MS002175 https://doaj.org/article/cf765c74416b485482fcceeb2f3717e0 EN eng American Geophysical Union (AGU) https://doi.org/10.1029/2020MS002175 https://doaj.org/toc/1942-2466 1942-2466 doi:10.1029/2020MS002175 https://doaj.org/article/cf765c74416b485482fcceeb2f3717e0 Journal of Advances in Modeling Earth Systems, Vol 12, Iss 12, Pp n/a-n/a (2020) kinetic energy backscatter viscosity closures mesoscale eddies ocean modeling eddy‐permitting resolution overdissipation Physical geography GB3-5030 Oceanography GC1-1581 article 2020 ftdoajarticles https://doi.org/10.1029/2020MS002175 2022-12-31T15:32:18Z Abstract Ocean models at eddy‐permitting resolution are generally overdissipative, damping the intensity of the mesoscale eddy field. To reduce overdissipation, we propose a simplified, kinematic energy backscatter parametrization built into the viscosity operator in conjunction with a new flow‐dependent coefficient of viscosity based on nearest neighbor velocity differences. The new scheme mitigates excessive dissipation of energy and improves global ocean simulations at eddy‐permitting resolution. We find that kinematic backscatter substantially raises simulated eddy kinetic energy, similar to an alternative, previously proposed dynamic backscatter parametrization. While dynamic backscatter is scale‐aware and energetically more consistent, its implementation is more complex. Furthermore, it turns out to be computationally more expensive, as it applies, among other things, an additional prognostic subgrid energy equation. The kinematic backscatter proposed here, by contrast, comes at no additional computational cost, following the principle of simplicity. Our primary focus is the discretization on triangular unstructured meshes with cell placement of velocities (an analog of B‐grids), as employed by the Finite‐volumE Sea ice‐Ocean Model (FESOM2). The kinematic backscatter scheme with the new viscosity coefficient is implemented in FESOM2 and tested in the simplified geometry of a zonally reentrant channel as well as in a global ocean simulation on a 1/4° mesh. This first version of the new kinematic backscatter needs to be tuned to the specific resolution regime of the simulation. However, the tuning relies on a single parameter, emphasizing the overall practicality of the approach. Article in Journal/Newspaper Sea ice Directory of Open Access Journals: DOAJ Articles Journal of Advances in Modeling Earth Systems 12 12 |
institution |
Open Polar |
collection |
Directory of Open Access Journals: DOAJ Articles |
op_collection_id |
ftdoajarticles |
language |
English |
topic |
kinetic energy backscatter viscosity closures mesoscale eddies ocean modeling eddy‐permitting resolution overdissipation Physical geography GB3-5030 Oceanography GC1-1581 |
spellingShingle |
kinetic energy backscatter viscosity closures mesoscale eddies ocean modeling eddy‐permitting resolution overdissipation Physical geography GB3-5030 Oceanography GC1-1581 S. Juricke S. Danilov N. Koldunov M. Oliver D. V. Sein D. Sidorenko Q. Wang A Kinematic Kinetic Energy Backscatter Parametrization: From Implementation to Global Ocean Simulations |
topic_facet |
kinetic energy backscatter viscosity closures mesoscale eddies ocean modeling eddy‐permitting resolution overdissipation Physical geography GB3-5030 Oceanography GC1-1581 |
description |
Abstract Ocean models at eddy‐permitting resolution are generally overdissipative, damping the intensity of the mesoscale eddy field. To reduce overdissipation, we propose a simplified, kinematic energy backscatter parametrization built into the viscosity operator in conjunction with a new flow‐dependent coefficient of viscosity based on nearest neighbor velocity differences. The new scheme mitigates excessive dissipation of energy and improves global ocean simulations at eddy‐permitting resolution. We find that kinematic backscatter substantially raises simulated eddy kinetic energy, similar to an alternative, previously proposed dynamic backscatter parametrization. While dynamic backscatter is scale‐aware and energetically more consistent, its implementation is more complex. Furthermore, it turns out to be computationally more expensive, as it applies, among other things, an additional prognostic subgrid energy equation. The kinematic backscatter proposed here, by contrast, comes at no additional computational cost, following the principle of simplicity. Our primary focus is the discretization on triangular unstructured meshes with cell placement of velocities (an analog of B‐grids), as employed by the Finite‐volumE Sea ice‐Ocean Model (FESOM2). The kinematic backscatter scheme with the new viscosity coefficient is implemented in FESOM2 and tested in the simplified geometry of a zonally reentrant channel as well as in a global ocean simulation on a 1/4° mesh. This first version of the new kinematic backscatter needs to be tuned to the specific resolution regime of the simulation. However, the tuning relies on a single parameter, emphasizing the overall practicality of the approach. |
format |
Article in Journal/Newspaper |
author |
S. Juricke S. Danilov N. Koldunov M. Oliver D. V. Sein D. Sidorenko Q. Wang |
author_facet |
S. Juricke S. Danilov N. Koldunov M. Oliver D. V. Sein D. Sidorenko Q. Wang |
author_sort |
S. Juricke |
title |
A Kinematic Kinetic Energy Backscatter Parametrization: From Implementation to Global Ocean Simulations |
title_short |
A Kinematic Kinetic Energy Backscatter Parametrization: From Implementation to Global Ocean Simulations |
title_full |
A Kinematic Kinetic Energy Backscatter Parametrization: From Implementation to Global Ocean Simulations |
title_fullStr |
A Kinematic Kinetic Energy Backscatter Parametrization: From Implementation to Global Ocean Simulations |
title_full_unstemmed |
A Kinematic Kinetic Energy Backscatter Parametrization: From Implementation to Global Ocean Simulations |
title_sort |
kinematic kinetic energy backscatter parametrization: from implementation to global ocean simulations |
publisher |
American Geophysical Union (AGU) |
publishDate |
2020 |
url |
https://doi.org/10.1029/2020MS002175 https://doaj.org/article/cf765c74416b485482fcceeb2f3717e0 |
genre |
Sea ice |
genre_facet |
Sea ice |
op_source |
Journal of Advances in Modeling Earth Systems, Vol 12, Iss 12, Pp n/a-n/a (2020) |
op_relation |
https://doi.org/10.1029/2020MS002175 https://doaj.org/toc/1942-2466 1942-2466 doi:10.1029/2020MS002175 https://doaj.org/article/cf765c74416b485482fcceeb2f3717e0 |
op_doi |
https://doi.org/10.1029/2020MS002175 |
container_title |
Journal of Advances in Modeling Earth Systems |
container_volume |
12 |
container_issue |
12 |
_version_ |
1766195318352773120 |