Submesoscale Vertical Velocities Enhance Tracer Subduction in an Idealized Antarctic Circumpolar Current

Dhruv Balwada, K. Shafer Smith, Ryan Abernathey

Research output: Contribution to journalArticle

Abstract

Upper-ocean submesoscale fronts, with their associated strong vertical velocities, are often claimed to play a significant role in subducting tracers into the interior. The role of these submesoscale processes in restratifying the mixed layer is now well recognized, but whether they simultaneously flux tracers through the base of the boundary layer remains an open question. We vary the resolution in a semirealistic channel model to control turbulent processes at various scales and study their influence on tracers. It is found that the submesoscale-permitting simulations flux far more tracer downward than the lower-resolution simulations: The 1-km simulation takes up 50% more tracer compared to the 20-km simulation, despite the increased restratifying influence of the resolved submesoscale processes. A full frequency-wave number cross-spectra of the vertical velocity and vertical tracer flux show that the high-frequency inertia-gravity waves that appear in the highest-resolution simulation play no role in irreversible downward tracer transport.

Original languageEnglish (US)
Pages (from-to)9790-9802
Number of pages13
JournalGeophysical Research Letters
Volume45
Issue number18
DOIs
StatePublished - Sep 28 2018

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Keywords

  • carbon uptake
  • mesoscales
  • ocean tracers
  • subduction
  • submesoscales
  • tracers

ASJC Scopus subject areas

  • Geophysics
  • Earth and Planetary Sciences(all)

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