scholarly journals Vertical eddy diffusion and nutrient supply to the surface mixed layer of the Antarctic Circumpolar Current

2003 ◽  
Vol 108 (C8) ◽  
Author(s):  
C. S. Law
Keyword(s):  
Mixed Layer ◽  
Antarctic Circumpolar Current ◽  
Eddy Diffusion ◽  
Nutrient Supply ◽  
Surface Mixed Layer ◽  
Circumpolar Current ◽  
The Antarctic ◽  
Vertical Eddy ◽  
Vertical Eddy Diffusion

scholarly journals Energetic Submesoscale Dynamics in the Ocean Interior

2020 ◽  
Vol 50 (3) ◽  
pp. 727-749 ◽  
Author(s):  
Lia Siegelman
Keyword(s):  
Mixed Layer ◽  
Gravity Waves ◽  
Gulf Stream ◽  
Antarctic Circumpolar Current ◽  
Internal Gravity Waves ◽  
Horizontal Resolution ◽  
Heat Fluxes ◽  
Surface Mixed Layer ◽  
Circumpolar Current ◽  
The Antarctic

AbstractSubmesoscale ocean processes, characterized by order-1 Rossby and Richardson numbers, are currently thought to be mainly confined to the ocean surface mixed layer, whereas the ocean interior is commonly assumed to be in quasigeostrophic equilibrium. Here, a realistic numerical simulation in the Antarctic Circumpolar Current, with a 1/48° horizontal resolution and tidal forcing, is used to demonstrate that the ocean interior departs from the quasigeostrophic regime down to depths of 900 m, that is, well below the mixed layer. Results highlight that, contrary to the classical paradigm, the ocean interior is strongly ageostrophic, with a pronounced cyclone–anticyclone asymmetry and a dominance of frontogenesis over frontolysis. Numerous vortices and filaments, from the surface down to 900 m, are characterized by large Rossby and low Richardson numbers, strong lateral gradients of buoyancy, and vigorous ageostrophic frontogenesis. These deep submesoscales fronts are only weakly affected by internal gravity waves and drive intense upward vertical heat fluxes, consistent with recent observations in the Antarctic Circumpolar Current and the Gulf Stream. As such, deep submesoscale fronts are an efficient pathway for the transport of heat from the ocean interior to the surface, suggesting the presence of an intensified oceanic restratification at depth.

scholarly journals On Cabbeling and Thermobaricity in the Surface Mixed Layer

2017 ◽  
Vol 47 (7) ◽  
pp. 1775-1787 ◽  
Author(s):  
K. D. Stewart ◽  
T. W. N. Haine ◽  
A. McC. Hogg ◽  
F. Roquet
Keyword(s):  
Equation Of State ◽  
Mixed Layer ◽  
Density Field ◽  
Surface Mixed Layer ◽  
Basin Scale ◽  
Ocean Models ◽  
Circumpolar Current ◽  
Earth’S Climate ◽  
Traditional Approaches ◽  
The Antarctic

AbstractThe surface mixed layer (ML) governs atmosphere–ocean fluxes, and thereby affects Earth’s climate. Accurate representation of ML processes in ocean models remains a challenge, however. The O(100) m deep ML exhibits substantial horizontal thermohaline gradients, despite being near-homogenous vertically, making it an ideal location for processes that result from the nonlinearity of the equation of state, such as cabbeling and thermobaricity. Traditional approaches to investigate these processes focus on their roles in interior water-mass transformation and are ill suited to examine their influence on the ML. However, given the climatic significance of the ML, quantifying the extent to which cabbeling and thermobaricity influence the ML density field offers insight into improving ML representations in ocean models. A recent simplified equation of state of seawater allows the local effects of cabbeling and thermobaric processes in the ML to be expressed analytically as functions of the local temperature gradient and ML depth. These simplified expressions are used to estimate the extent to which cabbeling and thermobaricity contribute to local ML density differences. These estimates compare well with values calculated directly using the complete nonlinear equation of state. Cabbeling and thermobaricity predominantly influence the ML density field poleward of 30°. Mixed layer thermobaricity is basin-scale and winter intensified, while ML cabbeling is perennial and localized to intense, zonally coherent regions associated with strong temperature fronts, such as the Antarctic Circumpolar Current and the Kuroshio and Gulf Stream Extensions. For latitudes between 40° and 50° in both hemispheres, the zonally averaged effects of ML cabbeling and ML thermobaricity can contribute on the order of 10% of the local ML density difference.

Mixed Layer Models and Their Application to Water Quality Problems

1994 ◽  
Vol 29 (2-3) ◽  
pp. 221-232
Author(s):  
M.J. McCormick
Keyword(s):  
Water Quality ◽  
Mixed Layer ◽  
Thermal Structure ◽  
Mass Conservation ◽  
Eddy Diffusion ◽  
Rate Of Change ◽  
Surface Mixed Layer ◽  
Storm Events ◽  
Quality Model ◽  
Mixing Processes

Abstract Four one-dimensional models which have been used to characterize surface mixed layer (ML) processes and the thermal structure are described. Although most any model can be calibrated to mimic surface water temperatures, it does not imply that the corresponding mixing processes are well described. Eddy diffusion or "K" models can exhibit this problem. If a ML model is to be useful for water quality applications, then it must be able to resolve storm events and, therefore, be able to simulate the ML depth, h, and its time rate of change, dh/dt. A general water quality model is derived from mass conservation principles to demonstrate how ML models can be used in a physically meaningful way to address water quality issues.

scholarly journals Nonlinear Differential Equations Modeling the Antarctic Circumpolar Current

2021 ◽  
Vol 23 (4) ◽  
Author(s):  
Jifeng Chu ◽  
Kateryna Marynets
Keyword(s):  
Fixed Point ◽  
Differential Equations ◽  
Boundary Conditions ◽  
Topological Degree ◽  
Antarctic Circumpolar Current ◽  
Fixed Point Theorems ◽  
Nonlinear Differential Equations ◽  
Existence Results ◽  
Circumpolar Current ◽  
The Antarctic

AbstractThe aim of this paper is to study one class of nonlinear differential equations, which model the Antarctic circumpolar current. We prove the existence results for such equations related to the geophysical relevant boundary conditions. First, based on the weighted eigenvalues and the theory of topological degree, we study the semilinear case. Secondly, the existence results for the sublinear and superlinear cases are proved by fixed point theorems.

scholarly journals Distinct Oceanic Microbiomes From Viruses to Protists Located Near the Antarctic Circumpolar Current

2018 ◽  
Vol 9 ◽  
Author(s):  
Flavia Flaviani ◽  
Declan C. Schroeder ◽  
Karen Lebret ◽  
Cecilia Balestreri ◽  
Andrea C. Highfield ◽  
...  
Keyword(s):  
Antarctic Circumpolar Current ◽  
Circumpolar Current ◽  
The Antarctic
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