Articles | Volume 17, issue 3
https://doi.org/10.5194/os-17-651-2021
© Author(s) 2021. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
https://doi.org/10.5194/os-17-651-2021
© Author(s) 2021. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
The mesoscale eddy field in the Lofoten Basin from high-resolution Lagrangian simulations
Johannes S. Dugstad
CORRESPONDING AUTHOR
Geophysical Institute, University of Bergen and Bjerknes Centre for Climate Research,
Bergen, Norway
Pål Erik Isachsen
Department of Geosciences, University of Oslo, Oslo, Norway
Norwegian Meteorological Institute, Oslo, Norway
Ilker Fer
Geophysical Institute, University of Bergen and Bjerknes Centre for Climate Research,
Bergen, Norway
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Kjersti Kalhagen, Ilker Fer, Till M. Baumann, Jon Albretsen, and Lukas Frank
EGUsphere, https://doi.org/10.5194/egusphere-2025-4402, https://doi.org/10.5194/egusphere-2025-4402, 2025
This preprint is open for discussion and under review for Ocean Science (OS).
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Warm Atlantic Water loses heat as it flows eastwards along the continental slope north of Svalbard. Year-long mooring records show the current is most energetic in autumn and winter, when it is the strongest and warmest. Also conversion from mean and potential energy to eddy energy peak in autumn and winter. An ocean model shows energy conversion also on the deeper, offshore side, suggesting eddies transport heat towards the basin, contributing to along-slope heat loss.
Mateusz Matuszak, Johannes Röhrs, Pål Erik Isachsen, and Martina Idžanović
Ocean Sci., 21, 401–418, https://doi.org/10.5194/os-21-401-2025, https://doi.org/10.5194/os-21-401-2025, 2025
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Lagrangian coherent structures (LCSs) describe material transport in ocean flow by describing transport and accumulation regions. We discuss the implications of model flow field uncertainty for finite-time Lyapunov exponents (FTLEs), which under certain conditions approximate LCSs. FTLEs add value to forecasting when they are certain and long-lived. Averaging FTLEs reveals where they are more certain and long-lived, often influenced by bottom topography.
Gillian Mary Damerell, Anthony Bosse, and Ilker Fer
EGUsphere, https://doi.org/10.5194/egusphere-2025-433, https://doi.org/10.5194/egusphere-2025-433, 2025
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The Lofoten Vortex is an unusual feature in the ocean: a permanent eddy which doesn’t dissipate as most eddies do. We have long thought that other eddies must merge into the Vortex in order to maintain its heat content and energetics, but such mergers are very difficult to observe due to their transient, unpredictable nature. For the first time, we have observed a merger using an ocean glider and high resolution satellite data and can document how the merger affects the properties of the Vortex.
Kjersti Kalhagen, Ragnheid Skogseth, Till M. Baumann, Eva Falck, and Ilker Fer
Ocean Sci., 20, 981–1001, https://doi.org/10.5194/os-20-981-2024, https://doi.org/10.5194/os-20-981-2024, 2024
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Atlantic water (AW) is a key driver of change in the Barents Sea. We studied an emerging pathway through the Svalbard Archipelago that allows AW to enter the Barents Sea. We found that the Atlantic sector near the study site has warmed over the past 2 decades; that Atlantic-origin waters intermittently enter the Barents Sea through the aforementioned pathway; and that heat transport is driven by tides, wind events, and variations in the upstream current system.
Eivind H. Kolås, Ilker Fer, and Till M. Baumann
Ocean Sci., 20, 895–916, https://doi.org/10.5194/os-20-895-2024, https://doi.org/10.5194/os-20-895-2024, 2024
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In the northwestern Barents Sea, we study the Barents Sea Polar Front formed by Atlantic Water meeting Polar Water. Analyses of ship and glider data from October 2020 to February 2021 show a density front with warm, salty water intruding under cold, fresh water. Short-term variability is linked to tidal currents and mesoscale eddies, influencing front position, density slopes and water mass transformation. Despite seasonal changes in the upper layers, the front remains stable below 100 m depth.
Ivan Kuznetsov, Benjamin Rabe, Alexey Androsov, Ying-Chih Fang, Mario Hoppmann, Alejandra Quintanilla-Zurita, Sven Harig, Sandra Tippenhauer, Kirstin Schulz, Volker Mohrholz, Ilker Fer, Vera Fofonova, and Markus Janout
Ocean Sci., 20, 759–777, https://doi.org/10.5194/os-20-759-2024, https://doi.org/10.5194/os-20-759-2024, 2024
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Our research introduces a tool for dynamically mapping the Arctic Ocean using data from the MOSAiC experiment. Incorporating extensive data into a model clarifies the ocean's structure and movement. Our findings on temperature, salinity, and currents reveal how water layers mix and identify areas of intense water movement. This enhances understanding of Arctic Ocean dynamics and supports climate impact studies. Our work is vital for comprehending this key region in global climate science.
Håvard Espenes, Pål Erik Isachsen, and Ole Anders Nøst
Ocean Sci., 19, 1633–1648, https://doi.org/10.5194/os-19-1633-2023, https://doi.org/10.5194/os-19-1633-2023, 2023
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We show that tidally generated eddies generated near the constriction of a channel can drive a strong and fluctuating flow field far downstream of the channel constriction itself. The velocity signal has been observed in other studies, but this is the first study linking it to a physical process. Eddies such as those we found are generated because of complex coastal geometry, suggesting that, for example, land-reclamation projects in channels may enhance current shear over a large area.
Eivind H. Kolås, Tore Mo-Bjørkelund, and Ilker Fer
Ocean Sci., 18, 389–400, https://doi.org/10.5194/os-18-389-2022, https://doi.org/10.5194/os-18-389-2022, 2022
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A turbulence instrument was installed on a light autonomous underwater vehicle (AUV) and deployed in the Barents Sea in February 2021. We present the data quality and discuss limitations when measuring turbulence from the AUV. AUV vibrations contaminate the turbulence measurements, yet the measurements were sufficiently cleaned when the AUV operated in turbulent environments. In quiescent environments the noise from the AUV became relatively large, making the turbulence measurements unreliable.
Eli Børve, Pål Erik Isachsen, and Ole Anders Nøst
Ocean Sci., 17, 1753–1773, https://doi.org/10.5194/os-17-1753-2021, https://doi.org/10.5194/os-17-1753-2021, 2021
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Non-linear tidal dynamics can produce prominent time-mean transport in coastal regions where strong tidal currents interact with topography. We investigate tidal-induced transport using a tidally driven ocean model for Lofoten–Vesterålen in northern Norway and find that both tidal pumping and tidal rectification can play an important role for time-mean transport in the region. The study emphasizes the importance of non-linear tidal dynamics for time-mean transport in complex coastal regions.
Zoe Koenig, Eivind H. Kolås, and Ilker Fer
Ocean Sci., 17, 365–381, https://doi.org/10.5194/os-17-365-2021, https://doi.org/10.5194/os-17-365-2021, 2021
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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.
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Short 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.
We quantify the mesoscale eddy field in the Lofoten Basin using Lagrangian model trajectories...