Articles | Volume 17, issue 1
Research article 19 Feb 2021
Research article | 19 Feb 2021
Structure and drivers of ocean mixing north of Svalbard in summer and fall 2018
Zoe Koenig et al.
No articles found.
Johannes S. Dugstad, Pål Erik Isachsen, and Ilker Fer
Ocean Sci. Discuss.,
Revised manuscript accepted for OSShort summary
We quantify the mesoscale eddy field in the Lofoten Basin using Lagrangian model trajectories and aim to estimate the relative importance of eddies compared to the ambient flow in transporting warm Atlantic Water to the Lofoten Basin as well as modifying it. Water properties are largely changed in eddies compared to the ambient flow. However, only a relatively small fraction of eddies is detected in the basin. The ambient flow therefore dominates the heat transport to the Lofoten Basin.
Ilker Fer, Anthony Bosse, and Johannes Dugstad
Ocean Sci., 16, 685–701,Short summary
We analyzed 14-month-long observations from moored instruments to describe the average features and the variability of the Norwegian Atlantic Slope Current at the Lofoten Escarpment (13°E, 69°N). The slope current varies strongly with depth and in time. Pulses of strong current occur, lasting for 1 to 2 weeks, and extend as deep as 600 m. The average volume transport is 2 x 106 m3 s-1.
Erik M. Bruvik, Ilker Fer, Kjetil Våge, and Peter M. Haugan
Ocean Sci., 16, 291–305,Short summary
A concept of small and slow ocean gliders or profiling floats with wings is explored. These robots or drones measure the ocean temperature and currents. Even if the speed is very slow, only 13 cm s1, it is possible to navigate the (simulated) ocean using a navigation method called Eulerian roaming. The slow speed and size conserve a lot of energy and enable scientific missions of years at sea.
Eivind Kolås and Ilker Fer
Ocean Sci., 14, 1603–1618,Short summary
Measurements of ocean currents, stratification and microstructure collected northwest of Svalbard are used to characterize the evolution of the warm Atlantic current. The measured turbulent heat flux is too small to account for the observed cooling rate of the current. The estimated contribution of diffusion by eddies could be limited to one half of the observed heat loss. Mixing in the bottom boundary layer, driven by cross-slope flow of buoyant water, can be important.
Jenny E. Ullgren, Elin Darelius, and Ilker Fer
Ocean Sci., 12, 451–470,Short summary
One-year long moored measurements of currents and hydrographic properties in the overflow region of the Faroe Bank Channel have provided a more accurate observational-based estimate of the volume transport, entrainment, and eddy diffusivities associated with the overflow plume. The data set resolves the temporal variability and covers the entire lateral and vertical extent of the plume.
E. Darelius, I. Fer, T. Rasmussen, C. Guo, and K. M. H. Larsen
Ocean Sci., 11, 855–871,Short summary
Quasi-regular eddies are known to be generated in the outflow of dense water through the Faroe Bank Channel. One year long mooring records from the plume region show that (1) the energy associated with the eddies varies by a factor of 10 throughout the year and (2) the frequency of the eddies shifts between 3 and 6 days and is related to the strength of the outflow. Similar variability is shown by a high-resolution regional model and the observations agree with theory on baroclinic instability.
I. Fer, M. Müller, and A. K. Peterson
Ocean Sci., 11, 287–304,Short summary
Over the Yermak Plateau northwest of Svalbard there is substantial energy conversion from barotropic to internal tides. Internal tides are trapped along the topography. An approximate local conversion-to-dissipation balance is found over shallows and also in the deep part of the sloping flanks. Dissipation of tidal energy can be a significant contributor to turbulent mixing and cooling of the Atlantic layer in the Arctic Ocean.
T. Vihma, R. Pirazzini, I. Fer, I. A. Renfrew, J. Sedlar, M. Tjernström, C. Lüpkes, T. Nygård, D. Notz, J. Weiss, D. Marsan, B. Cheng, G. Birnbaum, S. Gerland, D. Chechin, and J. C. Gascard
Atmos. Chem. Phys., 14, 9403–9450,
M. Bakhoday Paskyabi and I. Fer
Nonlin. Processes Geophys., 21, 713–733,
E. Støylen and I. Fer
Nonlin. Processes Geophys., 21, 87–100,
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The Arctic Ocean is a major sink for heat and salt for the global ocean. Ocean mixing contributes to this sink by mixing the Atlantic and Pacific waters with surrounding waters. We investigate the drivers of ocean mixing north of Svalbard based on observations collected during two research cruises in 2018 as part of the Nansen Legacy project. We found that wind and tidal forcing are the main drivers and that 1 % of the Atlantic Water heat loss can be attributed to vertical turbulent mixing.
The Arctic Ocean is a major sink for heat and salt for the global ocean. Ocean mixing...