Time-Dependent Eddy-Mean Energy Diagrams and Their Application to the Ocean

Chen, Ru; Thompson, Andrew F.; Flierl, Glenn R.

doi:10.1175/jpo-d-16-0012.1

Cited by 34 publications

(46 citation statements)

References 75 publications

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“…For ORCA025 and ORCA0083, our spectral KE budget results agree with the energy cycle in physical space diagnosed by [57] who showed a route of energy where mean KE and mean PE can generate eddy PE, which is then converted to baroclinic eddy KE and lastly barotropic eddy KE. This is also mostly in line with [58].…”

Section: Discussionsupporting

confidence: 87%

The Impact of Horizontal Resolution on Energy Transfers in Global Ocean Models

Kjellsson

Zanna

2017

Fluids

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Abstract:The ocean is a turbulent fluid with processes acting on a variety of spatio-temporal scales. The estimates of energy fluxes between length scales allows us to understand how the mean flow is maintained as well as how mesoscale eddies are formed and dissipated. Here, we quantify the kinetic energy budget in a suite of realistic global ocean models, with varying horizontal resolution and horizontal viscosity. We show that eddy-permitting ocean models have weaker kinetic energy cascades than eddy-resolving models due to discrepancies in the effect of wind forcing, horizontal viscosity, potential to kinetic energy conversion, and nonlinear interactions on the kinetic energy (KE) budget. However, the change in eddy kinetic energy between the eddy-permitting and the eddy-resolving model is not enough to noticeably change the scale where the inverse cascade arrests or the Rhines scale. In addition, we show that the mechanism by which baroclinic flows organise into barotropic flows is weaker at lower resolution, resulting in a more baroclinic flow. Hence, the horizontal resolution impacts the vertical structure of the simulated flow. Our results suggest that the effect of mesoscale eddies can be parameterised by enhancing the potential to kinetic energy conversion, i.e., the horizontal pressure gradients, or enhancing the inverse cascade of kinetic energy.

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Section: Discussionsupporting

confidence: 87%

The Impact of Horizontal Resolution on Energy Transfers in Global Ocean Models

Kjellsson

Zanna

2017

Fluids

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“…The energy transfer between the resolved flow and subgrid KE associated with the GM parameterization is formulated as

ė_{GM} = \frac{1}{H} \sum_{k} K_{GM} g_{k}^{'} false| \nabla_{σ} η_{k} |^{2},

where we assume a stacked shallow water model, as used in this study, and the sum is over all isopycnal layer interfaces, k , with height η k and reduced gravity gk′ . According to the QG energy cycle, potential energy extracted from the large‐scale flow by mesoscale eddies is converted first into eddy APE, with the final conversion to eddy KE being generally delayed (Chen et al, ). One could account for this pathway by including an additional explicit subgrid APE budget.…”

Section: A Scale‐aware Energy Budget‐based Eddy Parameterizationmentioning

confidence: 99%

Toward an Energetically Consistent, Resolution Aware Parameterization of Ocean Mesoscale Eddies

Jansen

Adcroft

Khani

et al. 2019

J Adv Model Earth Syst

138

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A subgrid‐scale eddy parameterization is developed, which makes use of an explicit eddy kinetic energy budget and can be applied at both “non‐eddying” and “eddy‐permitting” resolutions. The subgrid‐scale eddies exchange energy with the resolved flow in both directions via a parameterization of baroclinic instability (based on the established formulation of Gent and McWilliams) and biharmonic and negative Laplacian viscosity terms. This formulation represents the turbulent cascades of energy and enstrophy consistent with our current understanding of the turbulent eddy energy cycle. At the same time, the approach is simple and general enough to be readily implemented in ocean climate models, without adding significant computational cost. The closure has been implemented in the Modular Ocean Model Version 6 and tested in the “Neverworld” configuration, which employs an idealized analytically defined topography designed as a testbed for mesoscale eddy parameterizations. The parameterization performs well over a range of resolutions, seamlessly connecting non‐eddying and eddy‐resolving regimes.

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“…The fifth term, the "residual" term, includes the remaining terms when equation (6) is applied to equation (3). A similar decomposition of KE into specific parts was done by Chen et al (2016).…”

Section: Kementioning

confidence: 99%

Modeling Ocean Eddies on Antarctica's Cold Water Continental Shelves and Their Effects on Ice Shelf Basal Melting

et al. 2019

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Changes in the rate of ocean‐driven basal melting of Antarctica's ice shelves can alter the rate at which the grounded ice sheet loses mass and contributes to sea level change. Melt rates depend on the inflow of ocean heat, which occurs through steady circulation and eddy fluxes. Previous studies have demonstrated the importance of eddy fluxes for ice shelves affected by relatively warm intrusions of Circumpolar Deep Water. However, ice shelves on cold water continental shelves primarily melt from dense shelf water near the grounding line and from light surface water at the ice shelf front. Eddy effects on basal melt of these ice shelves have not been studied. We investigate where and when a regional ocean model of the Ross Sea resolves eddies and determine the effect of eddy processes on basal melt. The size of the eddies formed depends on water column stratification and latitude. We use simulations at horizontal grid resolutions of 5 and 1.5 km and, in the 1.5‐km model, vary the degree of topography smoothing. The higher‐resolution models generate about 2–2.5 times as many eddies as the low‐resolution model. In all simulations, eddies cross the ice shelf front in both directions. However, there is no significant change in basal melt between low‐ and high‐resolution simulations. We conclude that higher‐resolution models (<1 km) are required to better represent eddies in the Ross Sea but hypothesize that basal melt of the Ross Ice Shelf is relatively insensitive to our ability to fully resolve the eddy field.

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Time-Dependent Eddy-Mean Energy Diagrams and Their Application to the Ocean

Cited by 34 publications

References 75 publications

The Impact of Horizontal Resolution on Energy Transfers in Global Ocean Models

The Impact of Horizontal Resolution on Energy Transfers in Global Ocean Models

Toward an Energetically Consistent, Resolution Aware Parameterization of Ocean Mesoscale Eddies

Modeling Ocean Eddies on Antarctica's Cold Water Continental Shelves and Their Effects on Ice Shelf Basal Melting

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