Impact of Wave-Vortical Interactions on Oceanic Submesoscale Lateral Dispersion
- 17 September 2021
- journal article
- research article
- Published by American Meteorological Society in Journal of Physical Oceanography
- Vol. -1 (aop), 3495-3511
- https://doi.org/10.1175/jpo-d-20-0299.1
Abstract
Submesoscale lateral transport of Lagrangian particles in pycnocline conditions is investigated by means of idealized numerical simulations with reduced-interaction models. Using a projection technique, the models are formulated in terms of wave-mode and vortical-mode nonlinear interactions, and they range in complexity from full Boussinesq to waves-only and vortical-modes-only (QG) models. We find that, on these scales, most of the dispersion is done by vortical motions, but waves cannot be discounted because they play an important, albeit indirect, role. In particular, we show that waves are instrumental in filling out the spectra of vortical-mode energy at smaller scales through non-resonant vortex-wave-wave triad interactions. We demonstrate that a richer spectrum of vortical modes in the presence of waves enhances the effective lateral diffusivity, compared to QG. Waves also transfer energy upscale to vertically sheared horizontal flows which are a key ingredient for internal-wave shear dispersion. In the waves-only model, the dispersion rate is an order of magnitude smaller and is attributed entirely to internal-wave shear dispersion. Submesoscale lateral transport of Lagrangian particles in pycnocline conditions is investigated by means of idealized numerical simulations with reduced-interaction models. Using a projection technique, the models are formulated in terms of wave-mode and vortical-mode nonlinear interactions, and they range in complexity from full Boussinesq to waves-only and vortical-modes-only (QG) models. We find that, on these scales, most of the dispersion is done by vortical motions, but waves cannot be discounted because they play an important, albeit indirect, role. In particular, we show that waves are instrumental in filling out the spectra of vortical-mode energy at smaller scales through non-resonant vortex-wave-wave triad interactions. We demonstrate that a richer spectrum of vortical modes in the presence of waves enhances the effective lateral diffusivity, compared to QG. Waves also transfer energy upscale to vertically sheared horizontal flows which are a key ingredient for internal-wave shear dispersion. In the waves-only model, the dispersion rate is an order of magnitude smaller and is attributed entirely to internal-wave shear dispersion.Keywords
This publication has 68 references indexed in Scilit:
- Wave TurbulenceAnnual Review of Fluid Mechanics, 2011
- Fluid dynamics at the margin of rotational controlEnvironmental Fluid Mechanics, 2008
- Numerical Simulations of Lateral Dispersion by the Relaxation of Diapycnal Mixing EventsJournal of Physical Oceanography, 2005
- Stirring by Small-Scale Vortices Caused by Patchy MixingJournal of Physical Oceanography, 2005
- Isopycnal Dispersion in NATREJournal of Physical Oceanography, 2004
- Lateral dispersion over the continental shelf: Analysis of dye release experimentsJournal of Geophysical Research: Oceans, 2001
- Evolution of Isolated Interior Vortices in the OceanJournal of Physical Oceanography, 1997
- Averaging over fast gravity waves for geophysical flows with arbitaryCommunications in Partial Differential Equations, 1996
- Nonlinear interactions among internal gravity wavesReviews of Geophysics, 1986
- Internal Waves in the OceanAnnual Review of Fluid Mechanics, 1979