On the predictability of mode-1 internal tides

Dushaw, Brian D.; Worcester, Peter F.; Dzieciuch, Matthew A.

doi:10.1016/j.dsr.2011.04.002

Cited by 49 publications

(62 citation statements)

References 28 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In contrast, at abrupt ridges (e.g., HOME), well over half of the generated internal tide energy radiates away to dissipate elsewhere. In situ and altimetric measurements show that the majority of this energy goes into low-mode internal waves that may propagate thousands of kilometers (Zhao and Alford 2009;Dushaw et al 2011).…”

Section: Discussionmentioning

confidence: 99%

Global Patterns of Diapycnal Mixing from Measurements of the Turbulent Dissipation Rate

Waterhouse

MacKinnon

Nash

et al. 2014

Journal of Physical Oceanography

450

467

View full text Add to dashboard Cite

The authors present inferences of diapycnal diffusivity from a compilation of over 5200 microstructure profiles. As microstructure observations are sparse, these are supplemented with indirect measurements of mixing obtained from (i) Thorpe-scale overturns from moored profilers, a finescale parameterization applied to (ii) shipboard observations of upper-ocean shear, (iii) strain as measured by profiling floats, and (iv) shear and strain from full-depth lowered acoustic Doppler current profilers (LADCP) and CTD profiles. Vertical profiles of the turbulent dissipation rate are bottom enhanced over rough topography and abrupt, isolated ridges. The geography of depth-integrated dissipation rate shows spatial variability related to internal wave generation, suggesting one direct energy pathway to turbulence. The global-averaged diapycnal diffusivity below 1000-m depth is O(10 . The compiled microstructure observations sample a wide range of internal wave power inputs and topographic roughness, providing a dataset with which to estimate a representative global-averaged dissipation rate and diffusivity. However, there is strong regional variability in the ratio between local internal wave generation and local dissipation. In some regions, the depthintegrated dissipation rate is comparable to the estimated power input into the local internal wave field. In a few cases, more internal wave power is dissipated than locally generated, suggesting remote internal wave sources. However, at most locations the total power lost through turbulent dissipation is less than the input into the local internal wave field. This suggests dissipation elsewhere, such as continental margins.

show abstract

Section: Discussionmentioning

confidence: 99%

Global Patterns of Diapycnal Mixing from Measurements of the Turbulent Dissipation Rate

Waterhouse

MacKinnon

Nash

et al. 2014

Journal of Physical Oceanography

450

467

View full text Add to dashboard Cite

show abstract

“…Spectrally, this variation in arrival time smears the internal tide over a wider range of observed frequencies, which extend beyond the pure astronomical frequencies that force the barotropic tide (Dushaw et al, 2011). Nonlinear processes, due to interaction of the internal tide with the background fields or topography, can also alter the frequency content of the internal tide.…”

Section: Introductionmentioning

confidence: 99%

Are Any Coastal Internal Tides Predictable?

Nash¹,

Shroyer²,

Kelly³

et al. 2012

oceanog

View full text Add to dashboard Cite

“…As a result, a significant fraction of the mode-1 internal tide variance may be described by time-invariant harmonic constants near major sites of generation (Dushaw et al 2011). …”

Section: Introductionmentioning

confidence: 99%

“…This tends to scramble the phase of wave arrivals, and may create complex temporal or spatial interference patterns (Rainville et al 2010). As a result, propagating signals quickly become incoherent (Chavanne et al 2010;Zilberman et al 2011) so only a small fraction of the mode-1 variance can be described by harmonic analysis once the internal tide has traveled O(1000 km) from its source (Dushaw et al 2011).…”

Section: Introductionmentioning

confidence: 99%

The Unpredictable Nature of Internal Tides on Continental Shelves

Nash

Kelly

Shroyer

et al. 2012

Journal of Physical Oceanography

View full text Add to dashboard Cite

Packets of nonlinear internal waves (NLIWs) in a small area of the Mid-Atlantic Bight were 10 times more energetic during a local neap tide than during the preceding spring tide. This counterintuitive result cannot be explained if the waves are generated near the shelf break by the local barotropic tide since changes in shelfbreak stratification explain only a small fraction of the variability in barotropic to baroclinic conversion. Instead, this study suggests that the occurrence of strong NLIWs was caused by the shoaling of distantly generated internal tides with amplitudes that are uncorrelated with the local spring-neap cycle. An extensive set of moored observations show that NLIWs are correlated with the internal tide but uncorrelated with barotropic tide. Using harmonic analysis of a 40-day record, this study associates steady-phase motions at the shelf break with waves generated by the local barotropic tide and variable-phase motions with the shoaling of distantly generated internal tides. The dual sources of internal tide energy (local or remote) mean that shelf internal tides and NLIWs will be predictable with a local model only if the locally generated internal tides are significantly stronger than shoaling internal tides. Since the depth-integrated internal tide energy in the open ocean can greatly exceed that on the shelf, it is likely that shoaling internal tides control the energetics on shelves that are directly exposed to the open ocean.

show abstract

On the predictability of mode-1 internal tides

Cited by 49 publications

References 28 publications

Global Patterns of Diapycnal Mixing from Measurements of the Turbulent Dissipation Rate

Global Patterns of Diapycnal Mixing from Measurements of the Turbulent Dissipation Rate

Are Any Coastal Internal Tides Predictable?

The Unpredictable Nature of Internal Tides on Continental Shelves

Contact Info

Product

Resources

About