scholarly journals Measuring the Dissipation Rate of Turbulent Kinetic Energy in Strongly Stratified, Low‐Energy Environments: A Case Study From the Arctic Ocean

2018 ◽  
Vol 123 (8) ◽  
pp. 5459-5480 ◽  
Author(s):  
Benjamin Scheifele ◽  
Stephanie Waterman ◽  
Lucas Merckelbach ◽  
Jeffrey R. Carpenter
Keyword(s):  
Kinetic Energy ◽  
Arctic Ocean ◽  
Turbulent Kinetic Energy ◽  
Dissipation Rate ◽  
Low Energy ◽  
The Arctic ◽  
The Arctic Ocean

scholarly journals Eddy Kinetic Energy in the Arctic Ocean From a Global Simulation With a 1‐km Arctic

2020 ◽  
Vol 47 (14) ◽  
Author(s):  
Qiang Wang ◽  
Nikolay V. Koldunov ◽  
Sergey Danilov ◽  
Dmitry Sidorenko ◽  
Claudia Wekerle ◽  
...  
Keyword(s):  
Kinetic Energy ◽  
Arctic Ocean ◽  
Eddy Kinetic Energy ◽  
The Arctic ◽  
Global Simulation ◽  
The Arctic Ocean

Understanding the variability of the Eddy Kinetic Energy in the Arctic Ocean.

2021 ◽  
Author(s):  
Camille Lique ◽  
Heather Regan ◽  
Gianluca Meneghello ◽  
Claude Talandier
Keyword(s):  
Kinetic Energy ◽  
Arctic Ocean ◽  
Time Scales ◽  
Large Scale ◽  
Small Deformation ◽  
Arctic Basin ◽  
Temporal Variations ◽  
Eddy Kinetic Energy ◽  
The Arctic ◽  
The Arctic Ocean

<p>Mesoscale activity in the Arctic Ocean remains largely unexplored, owing primarily to the challenges of i) observing eddies in this ice-covered region and ii) modelling at such small deformation radius. In this talk, we will use results from a simulation performed with a high-resolution, eddy resolving model to investigate the spatial and temporal variations of the eddy kinetic energy (EKE) in the Arctic Basin. On average and in contrast to the typical open ocean conditions, the levels of mean and eddy kinetic energy are of the same order of magnitude, and EKE is intensified along the boundary and in the subsurface. On long time scales (interannual to decadal), EKE levels do not respond as expected to changes in the large scale circulation. This can be exemplified when looking at the spin up of the gyre that occurred in response to a strong surface input of momentum in 2007-2008. On seasonal time scales, the estimation of a Lorenz energy cycle allows us to investigate the drivers behind the peculiarities of the EKE field, and to understand the relative roles played by the atmospheric forcing for them.</p><p> </p>

scholarly journals Benthic Oxygen Uptake in the Arctic Ocean Margins - A Case Study at the Deep-Sea Observatory HAUSGARTEN (Fram Strait)

PLoS ONE ◽  
2015 ◽  
Vol 10 (10) ◽  
pp. e0138339 ◽  
Author(s):  
Cecile Cathalot ◽  
Christophe Rabouille ◽  
Eberhard Sauter ◽  
Ingo Schewe ◽  
Thomas Soltwedel
Keyword(s):  
Oxygen Uptake ◽  
Arctic Ocean ◽  
Deep Sea ◽  
The Arctic ◽  
Fram Strait ◽  
The Arctic Ocean

Quantifying mixing from standard observations: revisiting finescale parameterization in the Arctic Ocean

2021 ◽  
Author(s):  
Till Baumann ◽  
Ilker Fer ◽  
Kirstin Schulz ◽  
Volker Mohrholz ◽  
Janin Schaffer ◽  
...  
Keyword(s):  
Energy Dissipation ◽  
Internal Wave ◽  
Arctic Ocean ◽  
Wave Field ◽  
Turbulent Mixing ◽  
Dissipation Rate ◽  
The Arctic ◽  
Depth Range ◽  
The Arctic Ocean ◽  
Internal Wave Field

<p>Ocean mixing governs the vertical exchange of matter, heat and salt in the water column. In the Arctic Ocean, the vertical transport of heat due to turbulent mixing is ultimately coupled to the sea-ice cover, with immediate and far-reaching impacts on the climate and ecosystem. A detailed understanding and quantification of turbulent mixing is crucial to assess and predict the state of the changing Arctic Ocean. However, direct observations of turbulent mixing are complicated, expensive and sparse.</p><p>Finescale parameterization of turbulent energy dissipation allows for the quantification of mixing based on standard hydrographic observations such as velocity and density profiles. This method is based on the assumption that energy dissipation is achieved exclusively by cascading energy from large, observable scales to small scales by wave-to-wave interactions in the internal wave field, which in turn can be related to vertical diffusivity and hence turbulent fluxes. While the finescale parameterization is proved to be reliable at mid-latitudes, the Arctic Ocean internal wave field is distinct from the canonical mid-latitude spectrum and the applicability of the parameterization is not certain. Furthermore, in the historically quiescent Arctic, the application of finescale parameterization suffers from a generally low signal to noise ratio and processes violating the assumptions in the parameterization, such as double diffusion.  During the year-long MOSAiC expedition, both standard observations as well as specialized microstructure measurements were carried out continuously. We analyse dissipation rate and stratification measurements (from an MSS90L profiler) and 8-m vertical resolution current measurements (from a 75 kHz RDI acoustic Doppler current profiler) in the depth range from 70 -198 m, in the absence of thermohaline staircases or double-diffusive intrusions. Although the range of dissipation measurements is limited and spans 1e<sup>-11</sup> W kg<sup>-1</sup> to 8.8e<sup>-7</sup> W kg<sup>-1</sup>, direct comparisons between in-situ observations of dissipation rate and finescale parameterization provide a detailed insight into the capabilities and limitations of this method in various meteorological, oceanographic and geographic conditions. The aim is to provide guidance in how far standard oceanographic observations may be utilized to quantify mixing in past, current and future states of the Arctic Ocean.</p>

The Atlantic Water boundary current North of Svalbard in 2018-2019: background properties, dynamics and turbulence.

2020 ◽  
Author(s):  
Zoé Koenig ◽  
Eivind Kolås ◽  
Kjersti Kalhagen ◽  
Ilker Fer
Keyword(s):  
Arctic Ocean ◽  
Water Column ◽  
Mixed Layer ◽  
Dissipation Rate ◽  
Water Layer ◽  
Atlantic Water ◽  
The Arctic ◽  
Boundary Current ◽  
Turbulent Dissipation ◽  
The Arctic Ocean

<p></p><p>North of Svalbard is a key region for the Arctic Ocean heat and salt budget as it is the gateway for one of the main branches of Atlantic Water in the Arctic. As the Atlantic Water layer advances into the Arctic Ocean, its core deepens from about 250 m depth around the Yermak Plateau to 350 m in the Laptev Sea, and gets colder and less saline due to mixing with surrounding waters. The complex topography in the region facilitates vertical and horizontal exchanges between the water masses and, together with strong shear and tidal forcing driving increased mixing rates, impacts the heat and salt content of the Atlantic Water layer that will circulate the Arctic Ocean.</p><p></p><p>In summer 2018, 6 moorings organized in 2 arrays were deployed across the Atlantic Water Boundary current for a year, within the framework of the Nansen Legacy project. In parallel, turbulence structure in the Atlantic Water boundary current was measured north of Svalbard in two different periods (July and September), using a Vertical Microstructure Profiler (Rockland Scientific) in both cruises and a Microrider (Rockland Scientific) mounted on a Slocum glider in September.</p><p></p><p>Using mooring observations, we investigated the background properties of the Atlantic Water boundary current (transport, vertical structure, seasonal variations) and the possible sources of the low-frequency variations (period of more than 2 weeks).</p><p></p><p> Using observations during the cruise periods, we investigated changes in the mixed layer through the summer and the sources of vertical mixing in the water column. In the mixed layer, depth-integrated turbulent dissipation rate is about 10<sup>-4</sup> W m<sup>-2</sup>. Variations in the turbulent heat, salinity and buoyancy fluxes are strong, and hypothesized to be affected by the evolution of the surface meltwater layer through summer. When integrated over the Atlantic Water layer, the turbulent dissipation rate is about 3.10<sup>-3</sup> W m<sup>-2</sup>. Whilst the wind work exerted in the mixed layer accounts for most of the variability in the mixed layer, tidal forcing plays an important role in setting the dissipation rates deeper in the water column.</p><p></p>

The impact of multiple layering on internal wave transmission

2016 ◽  
Vol 789 ◽  
pp. 617-629 ◽  
Author(s):  
S. J. Ghaemsaidi ◽  
H. V. Dosser ◽  
L. Rainville ◽  
T. Peacock
Keyword(s):  
Experimental Study ◽  
Wave Propagation ◽  
Internal Wave ◽  
Arctic Ocean ◽  
The Arctic ◽  
Simplified Model ◽  
The Arctic Ocean ◽  
The Impact ◽  
Double Diffusive

Given the ubiquity of layering in environmental stratifications, an interesting example being double-diffusive staircase structures in the Arctic Ocean, we present the results of a joint theoretical and laboratory experimental study investigating the impact of multiple layering on internal wave propagation. We first present results for a simplified model that demonstrates the non-trivial impact of multiple layering. Thereafter, utilizing a weakly viscous linear model that can handle arbitrary vertical stratifications, we perform a comparison of theory with experiments. We conclude by applying this model to a case study of a staircase stratification profile obtained from the Arctic Ocean, finding a rich landscape of transmission behaviour.

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