scholarly journals Wave-induced steady streaming and net sediment transport in ocean bottom boundary layers

2009 ◽  
Author(s):  
L. E. Holmedal ◽  
D. Myrhaug
Keyword(s):  
Sediment Transport ◽  
Boundary Layers ◽  
Ocean Bottom ◽  
Bottom Boundary ◽  
Steady Streaming ◽  
Bottom Boundary Layers ◽  
Wave Induced

scholarly journals Nongeostrophic Baroclinic Instability over Sloping Bathymetry: Buoyant Flow Regime

2020 ◽  
Vol 50 (7) ◽  
pp. 1937-1956
Author(s):  
Lixin Qu ◽  
Robert Hetland
Keyword(s):  
Growth Rate ◽  
Flow Regime ◽  
Boundary Layers ◽  
Baroclinic Instability ◽  
Deep Ocean ◽  
Ocean Bottom ◽  
Coastal Zones ◽  
Buoyant Flow ◽  
Bottom Boundary ◽  
Bottom Boundary Layers

AbstractBaroclinic instabilities are important processes that enhance mixing and dispersion in the ocean. The presence of sloping bathymetry and the nongeostrophic effect influence the formation and evolution of baroclinic instabilities in oceanic bottom boundary layers and in coastal waters. This study explores two nongeostrophic baroclinic instability theories adapted to the scenario with sloping bathymetry and investigates the mechanism of the instability suppression (reduction in growth rate) in the buoyant flow regime. Both the two-layer and continuously stratified models reveal that the suppression is related to a new parameter, slope-relative Burger number Sr ≡ (M2/f2)(α + αp), where M2 is the horizontal buoyancy gradient, α is the bathymetry slope, and αp is the isopycnal slope. In the layer model, the instability growth rate linearly decreases with increasing Sr {the bulk form Sr = [U0/(H0f)](α + αp)}. In the continuously stratified model, the instability suppression intensifies with increasing Sr when the regime shifts from quasigeostrophic to nongeostrophic. The adapted theories are intrinsically applicable to deep ocean bottom boundary layers and could be conditionally applied to coastal buoyancy-driven flow. The slope-relative Burger number is related to the Richardson number by Sr = δrRi−1, where the slope-relative parameter is δr = (α + αp)/αp. Since energetic fronts in coastal zones are often characterized by low Ri, that implies potentially higher values of Sr, which is why baroclinic instabilities may be suppressed in the energetic regions where they would otherwise be expected to be ubiquitous according to the quasigeostrophic theory.

scholarly journals Turning Ocean Mixing Upside Down

2016 ◽  
Vol 46 (7) ◽  
pp. 2239-2261 ◽  
Author(s):  
Raffaele Ferrari ◽  
Ali Mashayek ◽  
Trevor J. McDougall ◽  
Maxim Nikurashin ◽  
Jean-Michael Campin
Keyword(s):  
Boundary Layers ◽  
Numerical Models ◽  
Meridional Overturning Circulation ◽  
Small Scale ◽  
Ocean Bottom ◽  
Overturning Circulation ◽  
Bottom Boundary ◽  
Bottom Boundary Layers ◽  
Meridional Overturning ◽  
Stratified Ocean

AbstractIt is generally understood that small-scale mixing, such as is caused by breaking internal waves, drives upwelling of the densest ocean waters that sink to the ocean bottom at high latitudes. However, the observational evidence that the strong turbulent fluxes generated by small-scale mixing in the stratified ocean interior are more vigorous close to the ocean bottom boundary than above implies that small-scale mixing converts light waters into denser ones, thus driving a net sinking of abyssal waters. Using a combination of theoretical ideas and numerical models, it is argued that abyssal waters upwell along weakly stratified boundary layers, where small-scale mixing of density decreases to zero to satisfy the no density flux condition at the ocean bottom. The abyssal ocean meridional overturning circulation is the small residual of a large net sinking of waters, driven by small-scale mixing in the stratified interior above the bottom boundary layers, and a slightly larger net upwelling, driven by the decay of small-scale mixing in the boundary layers. The crucial importance of upwelling along boundary layers in closing the abyssal overturning circulation is the main finding of this work.

Coastal bottom boundary layers and sediment transport

1993 ◽  
Vol 20 (3-4) ◽  
pp. 343-345
Author(s):  
Myrhaug D. Trondheim
Keyword(s):  
Sediment Transport ◽  
Boundary Layers ◽  
Bottom Boundary ◽  
Bottom Boundary Layers

Bottom Boundary Layers

2021 ◽  
Author(s):  
Stephen M. Henderson ◽  
Jeffrey R. Nielson
Keyword(s):  
Boundary Layers ◽  
Bottom Boundary ◽  
Bottom Boundary Layers
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