Mixing Driven by Breaking Nonlinear Internal Waves

N. L. Jones, G. N. Ivey, M. D. Rayson, S. M. Kelly

Research output: Contribution to journalArticlepeer-review

16 Scopus citations

Abstract

Non-linear internal waves (NLIW) are important to processes such as heat transfer, nutrient replenishment and sediment transport on continental shelves. Our unique field observations of shoaling NLIW of elevation revealed a variety of different wave shapes, varying from relatively symmetric waves, to waves with either steepened leading- or trailing-faces; many had evidence of trapped cores. The wave shape was related to the position of maximum density overturns and diapycnal mixing. We observed both shear (where sheared currents overcome the stabilizing effects of stratification) and convective (where the local velocity exceeds the wave propagation speed) instabilities. The elevated diapycnal mixing (>10−3 m2s−1) and heat flux (>500 Wm−2) were predominantly local to the NLIW of elevation packets, and were transported onshore 10s kilometers with the wave packets. We demonstrate that wave steepness may be a useful bulk property for the parameterization of wave-averaged diapycnal heat flux.

Original languageEnglish (US)
Article numbere2020GL089591
JournalGeophysical Research Letters
Volume47
Issue number19
DOIs
StatePublished - Oct 16 2020

Bibliographical note

Funding Information:
Australian Research Council Discovery Projects (DP 120103036 and DP 180101736), and an Office of Naval Research Naval International Cooperative Opportunities Project (N62909-11-1-7058) funded this work. We thank staff members from the Australian Institute of Marine Science, the Naval Research Laboratory, the University of Western Australia, and the crew of the R/V Solander, who aided in the collection of the data. We thank two anonymous reviewers for their input. We thank C. Bluteau for comments on a preliminary version of this manuscript. The PIL100 mooring is part of the Integrated Marine Observing System- national collaborative research infrastructure, supported by the Australian Government. The data used are available in the following repositories: BUBS data (https://doi.org/10.5281/zenodo.3840536); BUBS SBE56 data (https://doi.org/10.26182/5efab2ae66b48); PIL100 (https://doi.org/10.26182/5b7f5a0373924).

Funding Information:
Australian Research Council Discovery Projects (DP 120103036 and DP 180101736), and an Office of Naval Research Naval International Cooperative Opportunities Project (N62909‐11‐1‐7058) funded this work. We thank staff members from the Australian Institute of Marine Science, the Naval Research Laboratory, the University of Western Australia, and the crew of the R/V Solander, who aided in the collection of the data. We thank two anonymous reviewers for their input. We thank C. Bluteau for comments on a preliminary version of this manuscript. The PIL100 mooring is part of the Integrated Marine Observing System‐ national collaborative research infrastructure, supported by the Australian Government. The data used are available in the following repositories: BUBS data ( https://doi.org/10.5281/zenodo.3840536 ); BUBS SBE56 data ( https://doi.org/10.26182/5efab2ae66b48 ); PIL100 ( https://doi.org/10.26182/5b7f5a0373924 ).

Publisher Copyright:
©2020. The Authors.

Keywords

  • Australian Northwest Shelf
  • dipycnal mixing
  • internal waves
  • turbulence
  • vertical heat flux

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