Nonlinear Internal Tides in a Realistically Forced Global Ocean Simulation

Miguel S. Solano, Maarten C. Buijsman, Jay F. Shriver, Jorge Magalhaes, Jose da Silva, Christopher Jackson, Brian K. Arbic, Roy Barkan

Research output: Contribution to journalArticlepeer-review

4 Scopus citations

Abstract

The decay of the low-mode internal tide due to the superharmonic energy cascade is investigated in a realistically forced global Hybrid Coordinate Ocean Model simulation with 1/25° (4 km) horizontal grid spacing. Time-mean and depth-integrated supertidal kinetic energy is found to be largest near low-latitude internal tide generation sites, such as the Bay of Bengal, Amazon Shelf, and Mascarene Ridge. The supertidal kinetic energy can make up to 50% of the total internal tide kinetic energy several hundred kilometers from the generation sites. As opposed to the tidal flux divergence, the supertidal flux divergence does not correlate with the barotropic to baroclinic energy conversion. Instead, the time-mean and depth-integrated supertidal flux divergence correlates with the nonlinear kinetic energy transfers from (sub)tidal to supertidal frequency bands as estimated with a novel coarse-graining approach. The regular spaced banding patterns of the surface-intensified nonlinear energy transfers are attributed to semidiurnal mode 1 and mode 2 internal waves that interfere constructively at the surface. This causes patches where both surface tidal kinetic energy and nonlinear energy transfers are elevated. The simulated internal tide off the Amazon Shelf steepens significantly near these patches, generating solitary-like waves in good agreement with Synthetic Aperture Radar imagery. Globally, we find that regions of high supertidal energy flux also show a high correlation with observed instances of internal solitary waves.

Original languageEnglish
Article numbere2023JC019913
JournalJournal of Geophysical Research: Oceans
Volume128
Issue number12
DOIs
StatePublished - 1 Dec 2023
Externally publishedYes

Keywords

  • global ocean model
  • higher harmonic waves
  • internal tide steepening
  • nonlinear internal tides
  • solitary waves
  • wave-wave interactions

ASJC Scopus subject areas

  • Oceanography
  • Geophysics
  • Geochemistry and Petrology
  • Space and Planetary Science
  • Earth and Planetary Sciences (miscellaneous)

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