Scale-awareness in an eddy energy constrained mesoscale eddy parameterization
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arXiv
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| Autori principali: | , , , , , |
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| Natura: | Preprint |
| Pubblicazione: |
2023
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| _version_ | 1866910319266234368 |
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| author | Mak, Julian Maddison, James R. Marshall, David P. Ruan, Xi Wang, Yan Yeow, Liiyung |
| author_facet | Mak, Julian Maddison, James R. Marshall, David P. Ruan, Xi Wang, Yan Yeow, Liiyung |
| contents | There is an increasing interest in mesoscale eddy parameterizations that are scale-aware, normally interpreted to mean that a parameterization does not require re-tuning of parameters as the model resolution changes. Here we examine whether Gent--McWilliams (GM) based version of GEOMETRIC, a mesoscale eddy parameterization that is constrained by a parameterized eddy energy budget, is scale-aware in its energetics. It is generally known that GM-based schemes severely damp out explicit eddies, so the parameterized component would be expected to dominate across resolutions, and we might expect a negative answer to the question of energetic scale-awareness. A consideration of why GM-based schemes damp out explicit eddies leads a suggestion for what we term a splitting procedure: a definition of a `large-scale' field is sought, and the eddy-induced velocity from the GM-scheme is computed from and acts only on the large-scale field, allowing explicit and parameterized components to co-exist. Within the context of an idealized re-entrant channel model of the Southern Ocean, evidence is provided that the GM-based version of GEOMETRIC is scale-aware in the energetics as long as we employ a splitting procedure. The splitting procedure also leads to an improved representation of mean states without detrimental effects on the variability. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2306_08988 |
| institution | arXiv |
| publishDate | 2023 |
| record_format | arxiv |
| spellingShingle | Scale-awareness in an eddy energy constrained mesoscale eddy parameterization Mak, Julian Maddison, James R. Marshall, David P. Ruan, Xi Wang, Yan Yeow, Liiyung Atmospheric and Oceanic Physics Fluid Dynamics There is an increasing interest in mesoscale eddy parameterizations that are scale-aware, normally interpreted to mean that a parameterization does not require re-tuning of parameters as the model resolution changes. Here we examine whether Gent--McWilliams (GM) based version of GEOMETRIC, a mesoscale eddy parameterization that is constrained by a parameterized eddy energy budget, is scale-aware in its energetics. It is generally known that GM-based schemes severely damp out explicit eddies, so the parameterized component would be expected to dominate across resolutions, and we might expect a negative answer to the question of energetic scale-awareness. A consideration of why GM-based schemes damp out explicit eddies leads a suggestion for what we term a splitting procedure: a definition of a `large-scale' field is sought, and the eddy-induced velocity from the GM-scheme is computed from and acts only on the large-scale field, allowing explicit and parameterized components to co-exist. Within the context of an idealized re-entrant channel model of the Southern Ocean, evidence is provided that the GM-based version of GEOMETRIC is scale-aware in the energetics as long as we employ a splitting procedure. The splitting procedure also leads to an improved representation of mean states without detrimental effects on the variability. |
| title | Scale-awareness in an eddy energy constrained mesoscale eddy parameterization |
| topic | Atmospheric and Oceanic Physics Fluid Dynamics |
| url | https://arxiv.org/abs/2306.08988 |