An analytic model of observed small scale baroclinic currents in the Arctic Ocean.

Oceanic internal waves (IWs) propagate along density interfaces and are ubiquitous in stratified water. Their properties are influenced strongly by the nature and form of the upper and lower bounding surfaces of the containing basin(s) in which they propagate.&#160; As the Arctic Ocean evolves to a seasonally more ice-free state, the IW field will be affected by the change. The relationship between IW dynamics and ice is important in understanding (i) the general circulation and thermodynamics in the Arctic Ocean and (ii) local mixing processes that supply heat and nutrients from depth into upper layers, especially the photic zone. This, in turn, has important ramifications for sea ice formation processes and the state of local and regional ecosystems.&#160; Despite this, the effect of diminishing sea ice cover on the IW field (and vice versa) is not well established. A better understanding of IW dynamics in the Arctic Ocean and, in particular, how the IW field is affected by changes in both ice cover and stratification, is central in understanding how the rapidly changing Arctic will adapt to climate change.&#160;An experimental study of internal solitary waves (ISWs) propagating in a stably stratified two-layer fluid in which the upper boundary condition changes from open water to ice are studied for grease, level, and nilas ice. The experiments show that the internal wave-induced flow at the surface is capable of transporting sea-ice in the horizontal direction. In the level ice case, the transport speed of, relatively long ice floes, nondimensionalized by the wave speed is linearly dependent on the length of the ice floe nondimensionalized by the wave length. It will also be shown that bottom roughness associated with different ice types can cause varying degrees of vorticity and small-scale turbulence in the wave-induced boundary layer beneath the ice. Measures of turbulent kinetic energy dissipation under the ice are shown to be comparable to those at the wave density interface. Moreover, in cases where the ice floe protrudes into the pycnocline, interaction with the ice edge can cause the ISW to break or even be destroyed by the process. The results suggest that interaction between ISWs and sea ice may be an important mechanism for dissipation of ISW energy in the Arctic Ocean.&#160;AcknowledgementsThis work was funded through the EU Horizon 2020 Research and Innovation Programme Hydralab+.

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On the Circulation of Atlantic Water in the Arctic Ocean

Journal of Physical Oceanography ◽

10.1175/jpo-d-13-079.1 ◽

2013 ◽

Vol 43 (11) ◽

pp. 2352-2371 ◽

Cited By ~ 33

Author(s):

Michael A. Spall

Keyword(s):

Heat Flux ◽

Numerical Model ◽

Arctic Ocean ◽

Surface Heat Flux ◽

Atlantic Water ◽

Surface Heat ◽

The Arctic ◽

Analytic Model ◽

Boundary Current ◽

The Arctic Ocean

Abstract An idealized eddy-resolving numerical model and an analytic three-layer model are used to develop ideas about what controls the circulation of Atlantic Water in the Arctic Ocean. The numerical model is forced with a surface heat flux, uniform winds, and a source of low-salinity water near the surface around the perimeter of an Arctic basin. Despite this idealized configuration, the model is able to reproduce many general aspects of the Arctic Ocean circulation and hydrography, including exchange through Fram Strait, circulation of Atlantic Water, a halocline, ice cover and transport, surface heat flux, and a Beaufort Gyre. The analytic model depends on a nondimensional number, and provides theoretical estimates of the halocline depth, stratification, freshwater content, and baroclinic shear in the boundary current. An empirical relationship between freshwater content and sea surface height allows for a prediction of the transport of Atlantic Water in the cyclonic boundary current. Parameters typical of the Arctic Ocean produce a cyclonic boundary current of Atlantic Water of O(1 − 2 Sv; where 1 Sv ≡ 106 m3 s−1) and a halocline depth of O(200 m), in reasonable agreement with observations. The theory compares well with a series of numerical model calculations in which mixing and environmental parameters are varied, thus lending credibility to the dynamics of the analytic model. In these models, lateral eddy fluxes from the boundary and vertical diffusion in the interior are important drivers of the halocline and the circulation of Atlantic Water in the Arctic Ocean.

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Small-scale physical processes in the Arctic Ocean

Coastal and Estuarine Studies - Arctic Oceanography: Marginal Ice Zones and Continental Shelves ◽

10.1029/ce049p0097 ◽

1995 ◽

pp. 97-129 ◽

Cited By ~ 27

Author(s):

Laurie Padman

Keyword(s):

Arctic Ocean ◽

The Arctic ◽

Small Scale ◽

Physical Processes ◽

The Arctic Ocean

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The Arctic Ocean Circulation as simulated in a very high-resolution global ocean model (OCCAM)

Annals of Glaciology ◽

10.3189/172756401781818563 ◽

2001 ◽

Vol 33 ◽

pp. 567-576 ◽

Cited By ~ 2

Author(s):

Ye. Aksenov ◽

A.C. Coward

Keyword(s):

High Resolution ◽

Arctic Ocean ◽

Ocean Circulation ◽

Cox Model ◽

Ocean Model ◽

The Arctic ◽

Global Ocean ◽

Small Scale ◽

The Arctic Ocean ◽

Arctic Ocean Circulation

AbstractTo investigate the Arctic Ocean Circulation, results from a high-resolution fully global ocean model have been analyzed. The results come from two runs of the Ocean Circulation and Climate Advanced Modelling project (OCCAM) model, developed and run by the Southampton Oceanography Centre, at 1/4° × 1/4° and 1/8° × 1/8° resolution. The model is based on the Bryan-Semtner-Cox model and has 36 vertical levels. Enhancements include a free surface, an improved advection scheme and an improved treatment of the surface fresh-water flux. The model is forced with a monthly European Centre for Medium-range Weather Forecasts wind-stress climatology. It reproduces many of the fine-scale features found in the Arctic Ocean. The analysis concentrates on several of the key features, including the highly energetic eddy system in the western part of the Beaufort Sea, East Greenland West and Spitsbergen Currents and the detailed structure of the marginal currents along the Siberian and Canadian coasts. Much of the paper is focused on the water transport through the Bering and Fram Straits and through the Canadian Archipelago. Comparisons of the model net fluxes through the straits against observations are presented. The analyses of the results demonstrate the ability of the fine-resolution model to simulate features such as small-scale eddies and jets, which have some agreement with the limited observations available.

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