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Low- and high-frequency oscillatory winds synergistically enhance nutrient entrainment and phytoplankton at fronts
(AGU PublicationsJournal of Geophysical Research: Oceans, 2017-02-10)
When phytoplankton growth is limited by low nutrient concentrations, full-depth-integrated phytoplankton biomass increases in response to intermittent mixing events that bring nutrient-rich waters into the sunlit surface ...
Parameterization of Frontal Symmetric Instabilities. I: Theory for Resolved Fronts
(ElsevierOcean Modelling, 2017-01-01)
A parameterization is proposed for the effects of symmetric instability (SI) on a resolved front. The parameterization is dependent on external forcing by surface buoyancy loss and/or down-front winds, which reduce potential ...
Nonlinear evolution of linear optimal perturbations of strongly stratified shear layers
(Cambridge University PressJournal of Fluid Mechanics, 2017-08-25)
The Miles-Howard theorem states that a necessary condition for normal-mode instability in parallel, inviscid, steady stratified shear flows is that the minimum gradient Richardson number, $Ri_{g,min}$, is less than 1/4 ...
Mesoscale and Submesoscale Effects on Mixed Layer Depth in the Southern Ocean
(American Meteorological SocietyJournal of Physical Oceanography, 2017-09-01)
Submesoscale dynamics play a key role in setting the stratification of the ocean surface mixed layer and mediating air–sea exchange, making them especially relevant to anthropogenic carbon uptake and primary productivity ...
Modelling of partially-resolved oceanic symmetric instability
(ElsevierOcean Modelling, 2014-08-04)
A series of idealized numerical models have been developed to investigate the effects of partially resolved
symmetric instability (SI) in oceanic general circulation models. An analysis of the energetics of symmetric
instability ...
A new method for isolating turbulent states in transitional stratified plane Couette flow
(Cambridge University PressJournal of Fluid Mechanics, 2016-10-26)
We present a new adaptive control strategy to isolate and stabilize turbulent states in transitional, stably stratified plane Couette flow in which the gravitational acceleration (non-dimensionalized as the bulk Richardson ...
Robust identification of dynamically distinct regions in stratified turbulence
(Cambridge University PressJournal of Fluid Mechanics, 2016-10-18)
We present a new robust method for identifying three dynamically distinct regions in a stratified turbulent flow, which we characterise as quiescent flow, intermittent layers and turbulent patches. The method uses the ...
Self-similar mixing in stratified plane Couette flow for varying Prandtl number
(Cambridge University PressJournal of Fluid Mechanics, 2017-06-10)
We investigate fully developed turbulence in stratified plane Couette flows using direct numerical simulations similar to those reported by Deusebio et al. (J. Fluid Mech., vol. 781, 2015, pp. 298-329) expanding the range ...
Diapycnal mixing in layered stratified plane Couette flow quantified in a tracer-based coordinate
(Cambridge University PressJournal of Fluid Mechanics, 2017-07)
The mixing properties of statically stable density interfaces subject to imposed vertical shear are studied using direct numerical simulations of stratified plane Couette flow. The simulations are designed to investigate ...
Spontaneous Wave Generation at Strongly Strained Density Fronts
(American Meteorological SocietyJournal of Physical Oceanography, 2016-06-23)
A simple analytical model is presented describing the spontaneous generation of inertia–gravity waves at density fronts subjected to strong horizontal strain rates. The model considers fronts of arbitrary horizontal and ...