Optimizing internal wave drag in a forward barotropic model with semidiurnal tides

AbstractThe effects of a parameterized linear internal wave drag on the semidiurnal barotropic and baroclinic energetics of a realistically forced, three-dimensional global ocean model are analyzed. Although the main purpose of the parameterization is to improve the surface tides, it also influences the internal tides. The relatively coarse resolution of the model of ~8 km only permits the generation and propagation of the first three vertical modes. Hence, this wave drag parameterization represents the energy conversion to and the subsequent breaking of the unresolved high modes. The total tidal energy input and the spatial distribution of the barotropic energy loss agree with the Ocean Topography Experiment (TOPEX)/Poseidon (TPXO) tidal inversion model. The wave drag overestimates the high-mode conversion at ocean ridges as measured against regional high-resolution models. The wave drag also damps the low-mode internal tides as they propagate away from their generation sites. Hence, it can be considered a scattering parameterization, causing more than 50% of the deep-water dissipation of the internal tides. In the near field, most of the baroclinic dissipation is attributed to viscous and numerical dissipation. The far-field decay of the simulated internal tides is in agreement with satellite altimetry and falls within the broad range of Argo-inferred dissipation rates. In the simulation, about 12% of the semidiurnal internal tide energy generated in deep water reaches the continental margins.

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A Closure for Internal Wave–Mean Flow Interaction. Part II: Wave Drag

Journal of Physical Oceanography ◽

10.1175/jpo-d-16-0056.1 ◽

2017 ◽

Vol 47 (6) ◽

pp. 1403-1412 ◽

Cited By ~ 10

Author(s):

Carsten Eden ◽

Dirk Olbers

Keyword(s):

Wave Propagation ◽

Internal Wave ◽

Ocean Circulation ◽

Wave Drag ◽

Ocean Model ◽

Vertical Shear ◽

Mean Flow ◽

Flow Interaction ◽

Two Dimensional Flow ◽

Novel Concept

AbstractA novel concept for parameterizing internal wave–mean flow interaction in ocean circulation models is extended to an arbitrary two-dimensional flow with vertical shear. The concept is based on the description of the entire wave field by the wave-energy density in physical and wavenumber space and its prognostic computation by the radiative transfer equation integrated in wavenumber space. Energy compartments result for the horizontal direction of wave propagation as additional prognostic model variables, of which only four are taken here for simplicity. The mean flow is interpreted as residual velocities with respect to the wave activity. The effect of wave drag and energy exchange due to the vertical shear of the residual mean flow is then given simply by a vertical flux of momentum. This flux is related to the asymmetries in upward, downward, alongflow, and counterflow wave propagation described by the energy compartments. A numerical implementation in a realistic eddying ocean model shows that the wave drag effect is a significant sink of kinetic energy in the interior ocean.

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Internal wave drag in stratified flow over mountains on a beta plane

Quarterly Journal of the Royal Meteorological Society ◽

10.1002/qj.188 ◽

2008 ◽

Vol 134 (630) ◽

pp. 11-19 ◽

Cited By ~ 2

Author(s):

M. A. C. Teixeira ◽

Branko Grisogono

Keyword(s):

Internal Wave ◽

Stratified Flow ◽

Wave Drag ◽

Beta Plane

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The Immortal Science of Dead Water: Effects of Internal Wave Drag on Propagating Submerged Bodies

10.35248/2572-3103.19.7.191 ◽

2019 ◽

Vol 07 (01) ◽

Author(s):

Marco Danieletto ◽

Justin M Brown ◽

Timour Radko

Keyword(s):

Internal Wave ◽

Wave Drag ◽

Water Effects ◽

Dead Water

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The Impact of Small-Scale Topography on the Dynamical Balance of the Ocean

Journal of Physical Oceanography ◽

10.1175/jpo-d-12-056.1 ◽

2013 ◽

Vol 43 (3) ◽

pp. 647-668 ◽

Cited By ~ 23

Author(s):

Alberto C. Naveira Garabato ◽

A. J. George Nurser ◽

Robert B. Scott ◽

John A. Goff

Keyword(s):

Angular Momentum ◽

Internal Wave ◽

Ocean Circulation ◽

General Circulation ◽

General Circulation Models ◽

Wave Drag ◽

Small Scale ◽

Topographic Roughness ◽

Dynamical Balance ◽

The Impact

Abstract The impact of small-scale topography on the ocean’s dynamical balance is investigated by quantifying the rates at which internal wave drag extracts (angular) momentum and vorticity from the general circulation. The calculation exploits the recent advent of two near-global descriptions of topographic roughness on horizontal scales on the order of 1–10 km, which play a central role in the generation of internal lee waves by geostrophic flows impinging on topography and have been hitherto unresolved by bathymetric datasets and ocean general circulation models alike. It is found that, while internal wave drag is a minor contributor to the ocean’s dynamical balance over much of the globe, it is a significant player in the dynamics of extensive areas of the ocean, most notably the Antarctic Circumpolar Current and several regions of enhanced small-scale topographic variance in the equatorial and Southern Hemisphere oceans. There, the contribution of internal wave drag to the ocean’s (angular) momentum and vorticity balances is generally on the order of ten to a few tens of percent of the dominant source and sink terms in each dynamical budget, which are respectively associated with wind forcing and form drag by topography with horizontal scales from 500 to 1000 km. It is thus suggested that the representation of internal wave drag in general circulation models may lead to significant changes in the deep ocean circulation of those regions. A theoretical scaling is derived that captures the basic dependence of internal wave drag on topographic roughness and near-bottom flow speed for most oceanographically relevant regimes.

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