Articles | Volume 18, issue 2
https://doi.org/10.5194/os-18-389-2022
© Author(s) 2022. 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-18-389-2022
© Author(s) 2022. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Technical note
| 
24 Mar 2022
Technical note |
| 24 Mar 2022
| 24 Mar 2022
Technical note: Turbulence measurements from a light autonomous underwater vehicle
Geophysical Institute, University of Bergen and Bjerknes Center for Climate Research, Bergen, Norway
Tore Mo-Bjørkelund
Department of Marine Technology, Norwegian University of Science and Technology, Trondheim, Norway
Ilker Fer
Geophysical Institute, University of Bergen and Bjerknes Center for Climate Research, Bergen, Norway
Department of Arctic Geophysics, UNIS – The University Centre in Svalbard, Longyearbyen, Norway
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Eivind Kolås and Ilker Fer
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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
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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
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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
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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, https://doi.org/10.5194/acp-14-9403-2014, https://doi.org/10.5194/acp-14-9403-2014, 2014
M. Bakhoday Paskyabi and I. Fer
Nonlin. Processes Geophys., 21, 713–733, https://doi.org/10.5194/npg-21-713-2014, https://doi.org/10.5194/npg-21-713-2014, 2014
E. Støylen and I. Fer
Nonlin. Processes Geophys., 21, 87–100, https://doi.org/10.5194/npg-21-87-2014, https://doi.org/10.5194/npg-21-87-2014, 2014
Cited articles
Dhanak, M. R. and Holappa, K.: An Autonomous Ocean Turbulence
Measurement Platform, J. Atmos. Ocean. Tech., 16,
1506–1518, https://doi.org/10.1175/1520-0426(1999)016<1506:AAOTMP>2.0.CO;2, 1999. a
E.U. Copernicus Marine Service Information: Arctic Ocean – Sea and Ice Surface Temperature,
E.U. Copernicus Marine Service Information [data set], https://doi.org/10.48670/MOI-00130, 2020. a
Fer, I., Peterson, A. K., and Ullgren, J. E.: Microstructure Measurements
from an Underwater Glider in the Turbulent Faroe Bank Channel
Overflow, J. Atmos. Ocean. Tech., 31, 1128–1150,
https://doi.org/10.1175/JTECH-D-13-00221.1, 2014. a, b, c
Fer, I., Mo-Bjørkelund, T., and Kolås, E. H.: Dissipation measurements from
AUV transects across a surface temperature front in the Barents Sea, NMDC [data set],
https://doi.org/10.21335/NMDC-1821443450, 2021. a, b
Fossum, T. O., Norgren, P., Fer, I., Nilsen, F., Koenig, Z. C., and Ludvigsen,
M.: Adaptive Sampling of Surface Fronts in the Arctic Using an Autonomous
Underwater Vehicle, IEEE J. Oceanic Eng., 46, 1155–1164, https://doi.org/10.1109/JOE.2021.3070912, 2021. a
Frajka-Williams, E., Brearley, J. A., Nash, J. D., and Whalen, C. B.: Chapter
14 – New technological frontiers in ocean mixing, in: Ocean Mixing,
edited by: Meredith, M. and Garabato, A. N., 345–361, Elsevier,
https://doi.org/10.1016/B978-0-12-821512-8.00021-9, 2022. a, b
Garabato, A. C. N., Frajka-Williams, E. E., Spingys, C. P., Legg, S., Polzin,
K. L., Forryan, A., Abrahamsen, E. P., Buckingham, C. E., Griffies, S. M.,
McPhail, S. D., Nicholls, K. W., Thomas, L. N., and Meredith, M. P.: Rapid
mixing and exchange of deep-ocean waters in an abyssal boundary current,
P. Natl. Acad. Sci. USA, 116, 13233–13238,
https://doi.org/10.1073/pnas.1904087116, 2019. a
Gregg, M. C.: Ocean Mixing, Cambridge University Press,
https://doi.org/10.1017/9781316795439, 2021. a
Jakobsson, M., Mayer, L. A., Bringensparr, C., Castro, C. F., Mohammad, R.,
Johnson, P., Ketter, T., Accettella, D., Amblas, D., An, L., Arndt, J. E.,
Canals, M., Casamor, J. L., Chauché, N., Coakley, B., Danielson, S.,
Demarte, M., Dickson, M.-L., Dorschel, B., Dowdeswell, J. A., Dreutter, S.,
Fremand, A. C., Gallant, D., Hall, J. K., Hehemann, L., Hodnesdal, H., Hong,
J., Ivaldi, R., Kane, E., Klaucke, I., Krawczyk, D. W., Kristoffersen, Y.,
Kuipers, B. R., Millan, R., Masetti, G., Morlighem, M., Noormets, R.,
Prescott, M. M., Rebesco, M., Rignot, E., Semiletov, I., Tate, A. J.,
Travaglini, P., Velicogna, I., Weatherall, P., Weinrebe, W., Willis, J. K.,
Wood, M., Zarayskaya, Y., Zhang, T., Zimmermann, M., and Zinglersen, K. B.:
The International Bathymetric Chart of the Arctic Ocean Version
4.0, Scientific Data, 7, 176, https://doi.org/10.1038/s41597-020-0520-9, 2020. a
Levine, E. R. and Lueck, R. G.: Turbulence Measurement from an Autonomous
Underwater Vehicle, J. Atmos. Ocean. Tech., 16,
1533–1544, https://doi.org/10.1175/1520-0426(1999)016<1533:TMFAAU>2.0.CO;2, 1999. a, b
Lueck, R. G.: Horizontal and vertical turbulence profilers, in: Marine
Turbulence: Theories, observations and models. Results of the CARTUM
project, edited by: Baumert, H. Z., Simpson, J. H., and Sündermann, J.,
89–100, Cambridge University Press, Cambridge, UK, ISBN 978-05-2115-372-0, 2005. a
Lueck, R. G.: The statistics of turbulence measurements. Part 2: Shear
spectra and a new spectral model, J. Atmos. Ocean.
Tech., in review, 2022. a
Lueck, R. G., Wolk, F., and Yamazaki, H.: Oceanic Velocity Microstructure
Measurements in the 20th Century, J. Oceanogr., 58, 153–174,
https://doi.org/10.1023/A:1015837020019, 2002. a, b, c
McPhail, S., Templeton, R., Pebody, M., Roper, D., and Morrison, R.: Autosub
Long Range AUV Missions Under the Filchner and Ronne Ice
Shelves in the Weddell Sea, Antarctica – an Engineering
Perspective, in: OCEANS 2019 – Marseille, 1–8, IEEE,
https://doi.org/10.1109/OCEANSE.2019.8867206, 2019. a
Mostafapour, K., Nouri, N. M., and Zeinali, M.: The Effects of the Reynolds
Number on the Hydrodynamics Characteristics of an AUV, J.
Appl. Fluid Mech., 11, 343–352, https://doi.org/10.29252/jafm.11.02.28302, 2018. a
Nasmyth, P. W.: Oceanic turbulence, PhD thesis, University of British
Columbia, https://doi.org/10.14288/1.0302459, 1970. a, b
Nilsen, F., Fer, I., Baumann, T. M., Breivik, Ø., Czyz, C., Frank, L.,
Kalhagen, K., Koenig, Z., Kolås, E. H., Kral, S. T., Mabrouk, B. M. A.,
Mo-Bjørkelund, T., Muller, M., and Rabault, J.: Nansen Legacy Cruise
PC-2: Winter Process Cruise, Nansen Legacy Report Series, University of Tromsø – The Arctic University of Norway, https://doi.org/10.7557/nlrs.6324,
2021. a
Osborn, T. R. and Crawford, W. R.: An airfoil probe for measuring turbulent
velocity fluctuations in water, in: Air–Sea Interaction: Instruments
and Methods, edited by: Dobson, F., Hasse, L., and Davis, R., 369–386,
Plenum Press, New York, ISBN 978-14-6159-182-5, 1980. a
OSI SAF: Global Sea Ice Concentration (netCDF) – DMSP, EUMETSAT [data set],
https://doi.org/10.15770/EUM_SAF_OSI_NRT_2004, 2017. a
Palmer, M., Stephenson, G., Inall, M., Balfour, C., Düsterhus, A., and Green,
J.: Turbulence and mixing by internal waves in the Celtic Sea determined
from ocean glider microstructure measurements, J. Marine Syst.,
144, 57–69, https://doi.org/10.1016/j.jmarsys.2014.11.005, 2015. a, b
Panchev, S. and Kesich, D.: Energy spectrum of isotropic turbulence at large
wavenumbers, CR Acad. Bulg. Sci., 22, 627–630, 1969. a
Scheifele, B., Waterman, S., Merckelbach, L., and Carpenter, J. R.: Measuring
the Dissipation Rate of Turbulent Kinetic Energy in Strongly
Stratified, Low‐Energy Environments: A Case Study From the
Arctic Ocean, J. Geophys. Res.-Oceans, 123, 5459–5480,
https://doi.org/10.1029/2017JC013731, 2018. a
Schultze, L. K. P., Merckelbach, L. M., and Carpenter, J. R.: Turbulence and
Mixing in a Shallow Shelf Sea From Underwater Gliders, J. Geophys. Res.-Oceans, 122, 9092–9109, https://doi.org/10.1002/2017JC012872,
2017. a
Sousa, A., Madureira, L., Coelho, J., Pinto, J., Pereira, J., Borges Sousa, J.,
and Dias, P.: LAUV: The Man-Portable Autonomous Underwater
Vehicle, IFAC Proceedings Volumes, 45, 268–274,
https://doi.org/10.3182/20120410-3-PT-4028.00045, 2012.
a
Spingys, C. P., Garabato, A. C. N., Legg, S., Polzin, K. L., Abrahamsen, E. P.,
Buckingham, C. E., Forryan, A., and Frajka-Williams, E. E.: Mixing and
Transformation in a Deep Western Boundary Current: A Case
Study, J. Phys. Oceanogr., 51, 1205–1222,
https://doi.org/10.1175/JPO-D-20-0132.1, 2021. a
Thorpe, S. A., Osborn, T. R., Jackson, J. F. E., Hall, A. J., and Lueck, R. G.:
Measurements of Turbulence in the Upper-Ocean Mixing Layer Using
Autosub, J. Phys. Oceanogr., 33, 122–145,
https://doi.org/10.1175/1520-0485(2003)033<0122:MOTITU>2.0.CO;2, 2003. a
Yamazaki, H. and Osborn, T.: Dissipation estimates for stratified turbulence,
J. Geophys. Res.-Oceans, 95, 9739–9744,
https://doi.org/10.1029/JC095iC06p09739, 1990. a
Yamazaki, H., Lueck, R. G., and Osborn, T.: A Comparison of Turbulence
Data from a Submarine and a Vertical Profiler, J. Phys.
Oceanogr., 20, 1778–1786,
https://doi.org/10.1175/1520-0485(1990)020<1778:ACOTDF>2.0.CO;2, 1990. a, b
Short summary
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.
A turbulence instrument was installed on a light autonomous underwater vehicle (AUV) and...
