Articles | Volume 19, issue 4
https://doi.org/10.5194/os-19-1225-2023
© Author(s) 2023. 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-19-1225-2023
© Author(s) 2023. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Research article
| 
16 Aug 2023
Research article |
| 16 Aug 2023
| 16 Aug 2023
The Iceland–Faroe warm-water flow towards the Arctic estimated from satellite altimetry and in situ observations
Bogi Hansen
CORRESPONDING AUTHOR
Environmental Department, Faroe Marine Research Institute, Tórshavn, Faroe Islands
Karin M. H. Larsen
Environmental Department, Faroe Marine Research Institute, Tórshavn, Faroe Islands
Hjálmar Hátún
Environmental Department, Faroe Marine Research Institute, Tórshavn, Faroe Islands
Steffen M. Olsen
Danish Meteorological Institute, Copenhagen, Denmark
Andrea M. U. Gierisch
Danish Meteorological Institute, Copenhagen, Denmark
Svein Østerhus
NORCE Norwegian Research Centre, Bjerknes Centre for Climate
Research, Bergen, Norway
Sólveig R. Ólafsdóttir
Environmental Division, Marine and Freshwater Research Institute, Hafnarfjörður,
Iceland
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Compared to other freshwater sources, runoff from Iceland is small and usually flows into the Nordic Seas. Under certain wind conditions, it can, however, flow into the Iceland Basin and this occurred after 2014, when this region had already freshened from other causes. This explains why the surface freshening in this area became so extreme. The local and shallow character of this runoff allows it to have a disproportionate effect on vertical mixing, winter convection, and biological production.
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Two decades of observations of the Arctic Mediterranean (AM) exchanges show that the exchanges have been stable in terms of volume transport during a period when many other components of the global climate system have changed. The total AM import is found to be 9.1 Sv and has a seasonal variation in amplitude close to 1 Sv, and maximum import in October. Roughly one-third of the imported water leaves the AM as surface outflow.
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Preprint withdrawn
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Compared to other freshwater sources, runoff from Iceland is small and usually flows into the Nordic Seas. Under certain wind conditions, it can, however, flow into the Iceland Basin and this occurred after 2014, when this region had already freshened from other causes. This explains why the surface freshening in this area became so extreme. The local and shallow character of this runoff allows it to have a disproportionate effect on vertical mixing, winter convection, and biological production.
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Short summary
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The Faroe Bank Channel is one of the main passages for the flow of cold dense water from the Arctic into the depths of the world ocean where it feeds the deep branch of the AMOC. Based on in situ measurements, we show that the volume transport of this flow has been stable from 1995 to 2015. The water has warmed, but salinity increase has maintained its high density. Thus, this branch of the AMOC did not weaken during the last 2 decades, but increased its heat transport into the deep ocean.
Adrienne J. Sutton, Christopher L. Sabine, Richard A. Feely, Wei-Jun Cai, Meghan F. Cronin, Michael J. McPhaden, Julio M. Morell, Jan A. Newton, Jae-Hoon Noh, Sólveig R. Ólafsdóttir, Joseph E. Salisbury, Uwe Send, Douglas C. Vandemark, and Robert A. Weller
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Ocean carbonate observations from surface buoys reveal that marine life is currently exposed to conditions outside preindustrial bounds at 12 study locations around the world. Seasonal conditions in the California Current Ecosystem and Gulf of Maine also exceed thresholds that may impact shellfish larvae. High-resolution observations place long-term change in the context of large natural variability: a necessary step to understand ocean acidification impacts under real-world conditions.
S. M. Olsen, B. Hansen, S. Østerhus, D. Quadfasel, and H. Valdimarsson
Ocean Sci., 12, 545–560, https://doi.org/10.5194/os-12-545-2016, https://doi.org/10.5194/os-12-545-2016, 2016
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About half of the warm Atlantic water that enters the Norwegian Sea flows between Iceland and the Faroes. Here it crosses the Iceland-Faroe Ridge and dynamically interacts with the cold, dense and deep return flow across the ridge. This flow is not resolved in climate models and the lack of interaction prevents realistic heat anomaly propagation towards the Arctic.
E. Darelius, I. Fer, T. Rasmussen, C. Guo, and K. M. H. Larsen
Ocean Sci., 11, 855–871, https://doi.org/10.5194/os-11-855-2015, https://doi.org/10.5194/os-11-855-2015, 2015
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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.
B. Hansen, K. M. H. Larsen, H. Hátún, R. Kristiansen, E. Mortensen, and S. Østerhus
Ocean Sci., 11, 743–757, https://doi.org/10.5194/os-11-743-2015, https://doi.org/10.5194/os-11-743-2015, 2015
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The Faroe Current is the main ocean current transporting warm Atlantic water into the Arctic region and an important transporter of heat towards the Arctic. This study documents observed transport variations over two decades, from 1993 to 2013. It shows that the volume transport of Atlantic water in this current increased by 9% over the period, whereas the heat transport increased by 18%. This increase will have contributed to the observed warming and sea ice decline in the Arctic.
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E. Jeansson, R. G. J. Bellerby, I. Skjelvan, H. Frigstad, S. R. Ólafsdóttir, and J. Olafsson
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Long-term mean monthly fluxes of carbon and nutrients to the surface layer of the Iceland Sea are presented. From these fluxes we estimate primary production based on newly added nitrate (i.e. new production) and net community production (NCP). The annual new production in the Iceland Sea is estimated to 0.45±0.09mol N/m2/yr, and the net annual NCP to 7.3±1.0mol C/m2/yr. The typical C:N ratio during biological uptake is 9.0, challenging the Redfield C:N as the conversion factor in the area.
V. Racapé, N. Metzl, C. Pierre, G. Reverdin, P. D. Quay, and S. R. Olafsdottir
Biogeosciences, 11, 1683–1692, https://doi.org/10.5194/bg-11-1683-2014, https://doi.org/10.5194/bg-11-1683-2014, 2014
B. Berx, B. Hansen, S. Østerhus, K. M. Larsen, T. Sherwin, and K. Jochumsen
Ocean Sci., 9, 639–654, https://doi.org/10.5194/os-9-639-2013, https://doi.org/10.5194/os-9-639-2013, 2013
M. Eby, A. J. Weaver, K. Alexander, K. Zickfeld, A. Abe-Ouchi, A. A. Cimatoribus, E. Crespin, S. S. Drijfhout, N. R. Edwards, A. V. Eliseev, G. Feulner, T. Fichefet, C. E. Forest, H. Goosse, P. B. Holden, F. Joos, M. Kawamiya, D. Kicklighter, H. Kienert, K. Matsumoto, I. I. Mokhov, E. Monier, S. M. Olsen, J. O. P. Pedersen, M. Perrette, G. Philippon-Berthier, A. Ridgwell, A. Schlosser, T. Schneider von Deimling, G. Shaffer, R. S. Smith, R. Spahni, A. P. Sokolov, M. Steinacher, K. Tachiiri, K. Tokos, M. Yoshimori, N. Zeng, and F. Zhao
Clim. Past, 9, 1111–1140, https://doi.org/10.5194/cp-9-1111-2013, https://doi.org/10.5194/cp-9-1111-2013, 2013
Related subject area
Approach: In situ Observations | Properties and processes: Overturning circulation, gyres and water masses
Water properties and bottom water patterns in hadal trench environments
Long-term eddy modulation affects the meridional asymmetry of the halocline in the Beaufort Gyre
Comparing observed and modelled components of the Atlantic Meridional Overturning Circulation at 26°N
Southern Ocean deep mixing band emerges from a competition between winter buoyancy loss and upper stratification strength
Technical note: Determining Arctic Ocean halocline and cold halostad depths based on vertical stability
Jessica Kolbusz, Jan Zika, Charitha Pattiaratchi, and Alan Jamieson
Ocean Sci., 20, 123–140, https://doi.org/10.5194/os-20-123-2024, https://doi.org/10.5194/os-20-123-2024, 2024
Short summary
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We collected observations of the ocean environment at depths over 6000 m in the Southern Ocean, Indian Ocean, and western Pacific using sensor-equipped landers. We found that trench locations impact the water characteristics over these depths. Moving northward, they generally warmed but differed due to their position along bottom water circulation paths. These insights stress the importance of further research in understanding the environment of these deep regions and their importance.
Jinling Lu, Ling Du, and Shuhao Tao
Ocean Sci., 19, 1773–1789, https://doi.org/10.5194/os-19-1773-2023, https://doi.org/10.5194/os-19-1773-2023, 2023
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With the recent developments in observations and reanalysis data in the Beaufort Gyre, we investigate an improved understanding of eddy activity and asymmetrical halocline variability in the upper ocean. The halocline structures on the southern and northern sides of the central gyre have tended to be identical since 2014. The results suggest that enhanced eddy modulation through eddy fluxes influences oceanic stratification, resulting in reduced meridional asymmetry of the halocline.
Harry Bryden, Sybren Drijfhout, Jennifer Mecking, and Wilco Hazeleger
EGUsphere, https://doi.org/10.5194/egusphere-2023-2688, https://doi.org/10.5194/egusphere-2023-2688, 2023
Short summary
Short summary
There is widespread interest in whether the Gulf Stream will decline under global warming. We analyse 19 coupled climate model projections of the AMOC over the 21st century. Model consensus is that the AMOC will decline by about 40 %. The decline is due to reductions in northward Gulf Stream transport and southward deep boundary current transport. Whilst the wind-driven Gulf Stream decreases by 4 Sv, most of the decrease in Gulf Stream is due to reduction of 7 Sv in its thermohaline component.
Romain Caneill, Fabien Roquet, and Jonas Nycander
EGUsphere, https://doi.org/10.5194/egusphere-2023-2404, https://doi.org/10.5194/egusphere-2023-2404, 2023
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In winter, heat loss increases density at the surface of the Southern Ocean. This increase of density creates a mixed layer deeper than 250m only in a narrow deep mixing band (DMB) located around 50°S. We found that north of the DMB, the stratification is too strong to be eroded, so mixed layers are shallower. The density of cold water is almost not impacted by temperature changes. Thus, heat loss does not increase significantly the density south of the DMB, so no deep mixed layers are produced.
Enrico P. Metzner and Marc Salzmann
Ocean Sci., 19, 1453–1464, https://doi.org/10.5194/os-19-1453-2023, https://doi.org/10.5194/os-19-1453-2023, 2023
Short summary
Short summary
The Arctic Ocean cold halocline separates the cold surface mixed layer from the underlying warm Atlantic Water, and thus provides a precondition for sea ice formation. Here, we introduce a new method for detecting the halocline base and compare it to two existing methods. We show that the largest differences between the methods are found in the regions that are most prone to a halocline retreat in a warming climate, and we discuss the advantages and disadvantages of the three methods.
Cited articles
Arias, P. A., Bellouin, N., Coppola, E., Jones, R. G., Krinner, G., Marotzke, J., Naik, V., Palmer, M. D., Plattner, G.-K., Rogelj, J., Rojas, M., Sillmann, J., Storelvmo, T., Thorne, P. W., Trewin, B., Achuta Rao, K., Adhikary, B., Allan, R. P., Armour, K., Bala, G., Barimalala, R., Berger, S., Canadell, J. G., Cassou, C., Cherchi, A., Collins, W., Collins, W. D., Connors, S. L., Corti, S., Cruz, F., Dentener, F. J., Dereczynski, C., Di Luca, A., Diongue Niang, A., Doblas-Reyes, F. J., Dosio, A., Douville, H., Engelbrecht, F., Eyring, V., Fischer, E., Forster, P., Fox-Kemper, B., Fuglestvedt, J. S., Fyfe, J. C., Gillett, N. P., Goldfarb, L., Gorodetskaya, I., Gutierrez, J. M., Hamdi, R., Hawkins, E., Hewitt, H. T., Hope, P., Islam, A. S., Jones, C., Kaufman, D. S., Kopp, R. E., Kosaka, Y., Kossin, J., Krakovska, S., Lee, J.-Y., Li, J., Mauritsen, T., Maycock, T. K., Meinshausen, M., Min, S.-K., Monteiro, P. M. S., Ngo-Duc, T., Otto, F., Pinto, I., Pirani, A., Raghavan, K., Ranasinghe, R., Ruane, A. C., Ruiz, L., Sallée, J.-B., Samset, B. H., Sathyendranath, S., Seneviratne, S. I., Sörensson, A. A., Szopa, S., Takayabu, I., Tréguier, A.-M., van den Hurk, B., Vautard, R., von Schuckmann, K., Zaehle, S., Zhang, X., and Zickfeld, K.: Technical Summary, in: Climate Change 2021: The
Physical Science Basis. Contribution of Working Group I to the Sixth
Assessment Report of the Intergovernmental Panel on Climate Change, edited
by: Masson-Delmotte, V., Zhai, P., Pirani, A., Connors, S. L., Péan, C., Berger, S., Caud, N., Chen, Y., Goldfarb, Z., Gomis, M. I., Huang, M., Leitzell, K., Lonnoy, E., Matthews, J. B. R., Maycock, T. K., Waterfield, T., Yelekçi, O., Yu, R., and Zhou, B., Cambridge University Press, Cambridge, United
Kingdom and New York, NY, USA, 33–144,
https://doi.org/10.1017/9781009157896.002, 2021.
Beaird, N. L., Rhines, P. B., and Eriksen, C. C.: Overflow waters at the
Iceland-Faroe Ridge observed in multiyear Seaglider surveys, J. Phys.
Oceanogr., 43, 2334–2351, https://doi.org/10.1175/JPO-D-13-029.1, 2013.
Beaird, N. L., Rhines, P. B., and Eriksen, C. C.: Observations of seasonal
subduction at the Iceland-Faroe Front, J. Geophys. Res.-Oceans, 121,
4026–4040, https://doi.org/10.1002/2015JC011501, 2016.
Berx, B., Hansen, B., Østerhus, S., Larsen, K. M., Sherwin, T., and Jochumsen, K.: Combining in situ measurements and altimetry to estimate volume, heat and salt transport variability through the Faroe–Shetland Channel, Ocean Sci., 9, 639–654, https://doi.org/10.5194/os-9-639-2013, 2013.
Darelius, E., Fer, I., and Quadfasel, D.: Faroe Bank Channel overflow:
mesoscale variability, J. Phys. Oceanogr., 41, 2137–2154,
https://doi.org/10.1175/JPO-D-11-035.1, 2011.
Darelius, E., Fer, I., Rasmussen, T., Guo, C., and Larsen, K. M. H.: On the modulation of the periodicity of the Faroe Bank Channel overflow instabilities, Ocean Sci., 11, 855–871, https://doi.org/10.5194/os-11-855-2015, 2015.
Dickson, R. R. and Brown, J.: The production of North Atlantic deep water,
sources, rates, and pathways, J. Geophys. Res., 99, 12319–12341,
https://doi.org/10.1029/94JC00530, 1994.
ENVOFAR: ENVOFAR, http://www.envofar.fo, last access: 10 August 2023.
Geyer, F., Østerhus, S., Hansen, B., and Quadfasel, D.: Observations of
highly regular oscillations in the overflow plume downstream of the Faroe
Bank Channel, J. Geophys. Res., 111, C12020,
https://doi.org/10.1029/2006JC003693, 2006.
Hansen, B. and Meincke, J.: Eddies and meanders in the Iceland-Faroe Ridge
area, Deep-Sea Res, 26, 1067–1082,
https://doi.org/10.1016/0198-0149(79)90048-7, 1979.
Hansen, B. and Østerhus, S.: North Atlantic–Nordic Seas exchanges, Prog.
Oceanogr., 45, 109–208, https://doi.org/10.1016/s0079-6611(99)00052-x,
2000.
Hansen, B., Østerhus, S., Hátún, H., Kristiansen, R., and Larsen,
K. M. H.: The Iceland-Faroe inflow of Atlantic water to the Nordic Seas,
Prog. Oceanogr., 59, 4, 443–474,
https://doi.org/10.1016/j.pocean.2003.10.003, 2003.
Hansen, B., Hátún, H., Kristiansen, R., Olsen, S. M., and Østerhus, S.: Stability and forcing of the Iceland-Faroe inflow of water, heat, and salt to the Arctic, Ocean Sci., 6, 1013–1026, https://doi.org/10.5194/os-6-1013-2010, 2010.
Hansen, B., Larsen, K. M. H., Hátún, H., Kristiansen, R., Mortensen, E., and Østerhus, S.: Transport of volume, heat, and salt towards the Arctic in the Faroe Current 1993–2013, Ocean Sci., 11, 743–757, https://doi.org/10.5194/os-11-743-2015, 2015.
Hansen, B., Larsen, K. M. H., Kristiansen, R., Mortensen, E., Quadfasel, D.,
Jochumsen, K., and Østerhus, S.: Observations from the WOW field
experiment in the Western Valley 2016–2017 Data report, Havstovan nr.:
17-03, Technical report, http://www.hav.fo/PDF/Ritgerdir/2017/TecRep1703.pdf
(last access: 27 June 2023), 2017.
Hansen, B., Larsen, K. M. H., Olsen, S. M., Quadfasel, D., Jochumsen, K., and Østerhus, S.: Overflow of cold water across the Iceland–Faroe Ridge through the Western Valley, Ocean Sci., 14, 871–885, https://doi.org/10.5194/os-14-871-2018, 2018.
Hansen, B., Larsen, K. M. H., and Hátún, H.: Monitoring the velocity
structure of the Faroe Current, Havstovan Technical Report Nr.: 19-01,
http://www.hav.fo/PDF/Ritgerdir/2019/TechRep1901.pdf (last access: 27 June 2023), 2019.
Hansen, B., Larsen, K. M. H., Hátún, H., and Østerhus, S.:
Atlantic water extent on the Faroe Current monitoring section, Havstovan
Technical Report Nr.: 20-03,
http://www.hav.fo/PDF/Ritgerdir/2020/TechRep2003.pdf (last access: 27 June 2023), 2020.
Hátún, H., Hansen, B., and Haugan, P.: Using an ”inverse dynamic
method” to determine temperature and salinity fields from ADCP
measurements, J. Atmos. Ocean. Tech., 21, 527–534,
https://doi.org/10.1175/1520-0426(2004)021<0527:UAIDMT>2.0.CO;2, 2004.
Helland-Hansen, B. and Nansen, F.: The Norwegian Sea, its physical
oceanography. Based on the Norwegian researches 1900–1904, Report on
Norwegian fishery and marine-investigations Vol. 11 1909 No.2, 390 pp. +
325 plates, https://imr.brage.unit.no/imr-xmlui/handle/11250/114874 (last access: 10 August 2023), 1909.
Hermann, F.: Hydrographic Conditions in the South-Western Part of the
Norwegian Sea, Ann. Biol. Cons. Int. Explor. Mer., 5, 19–21, 1949.
Hermann, F.: The TS diagram analysis of the water masses over the
Iceland-Faroe Ridge and in the Faroe Bank Channel, Rapp. PV Reun. Cons. Int.
Explor. Mer., 157, 139–149, 1967.
Heuzé, C. and Årthun, M.: The Atlantic inflow across the
Greenland-Scotland ridge in global climate models (CMIP5), Elem. Sci. Anth.,
7, 16, https://doi.org/10.1525/elementa.354, 2019.
Jónsson, S. and Valdimarsson, H.: Water mass transport variability to
the North Icelandic shelf, 1994–2010, ICES J. Mar. Sci., 69, 809–815,
https://doi.org/10.1093/icesjms/fss024, 2012.
Knudsen, M.: Den Danske Ingolf-expedition, Bianco Lunos Kgl. Hof-Bogtrykkeri
(F. Dreyer), København, 1, 21–154, 1898.
Koman, G., Johns, W. E., Houk, A., Houpert, L., and Li, F.: Circulation and
overturning in the eastern North Atlantic subpolar gyre, Prog. Oceanogr.,
208, 102884, https://doi.org/10.1016/j.pocean.2022.102884, 2022.
Larsen, K. M. H., Hátún, H., Hansen, B., and Kristiansen, R.:
Atlantic water in the Faroe area: sources and variability, ICES J. Mar.
Sci., 69, 802–808, https://doi.org/10.1093/icesjms/fss028, 2012.
Logemann, K., Ólafsson, J., Snorrason, Á., Valdimarsson, H., and Marteinsdóttir, G.: The circulation of Icelandic waters – a modelling study, Ocean Sci., 9, 931–955, https://doi.org/10.5194/os-9-931-2013, 2013.
Lozier, M. S., Li, F., Bacon, S., Bahr, F., Bower, A. S., Cunningham, S. A.,
de Jong, M. F., de Steur, L., deYoung, B., Fischer, J., Gary, S. F.,
Greenan, B. J. W., Holliday, N. P., Houk, A., Houpert, L., Inall, M. E.,
Johns, W. E., Johnson, H. L., Johnson, C., Karstensen, J., Koman, G., Le
Bras, I. A., Lin, X., Mackay, N., Marshall, D. P., Mercier, H., Oltmanns,
M., Pickart, R. S., Ramsey, A. L., Rayner, D., Straneo, F., Thierry, V.,
Torres, D. J., Williams, R. G., Wilson, C., Yang, J., Yashayaev, I., and
Zhao, J.: A sea change in our view of overturning in the subpolar North
Atlantic, Science, 363, 516–521, https://doi.org/10.1126/science.aau6592,
2019.
Mayer, M., Tsubouchi, T., Winkelbauer, S., Larsen, K. M. H., Berx, B.,
Macrander, A., Iovino, D., Jónsson, S., and Renshaw, R.: Recent
variations in oceanic transports across the Greenland-Scotland Ridge,
Copernicus Ocean State Report, 7, J.
Oper. Oceanogr., accepted, 2023.
McCartney, M. S. and Talley, L. D.: Warm-to-Cold Water Conversion in the
Northern North Atlantic Ocean, J. Phys. Oceanogr., 14, 922–935,
https://doi.org/10.1175/1520-0485(1984)014<0922:WTCWCI>2.0.CO;2, 1984.
Meincke, J.: The Hydrographic Section along the Iceland-Faroe Ridge carried
out by R.V. “Anton Dohrn” in 1959–1971, Ber. Dt. Wiss. Kommiss.
Meeresforsch., 22, 372—384, 1972.
Meincke, J.: On the distribution of low salinity intermediate waters around
the Faroes, Deutsche Hydrographische Zeitschrift, 31, 50–64,
https://doi.org/10.1007/bf02226000, 1978.
Meincke, J.: The Modern Current Regime Across the Greenland-Scotland Ridge,
in: Structure and Development of the Greenland-Scotland Ridge, edited by:
Bott, M. H. P., Saxov, S., Talwani, M., and Thiede, J., NATO Conference
Series (IV Marine Science), 8, Springer, Boston, MA, 637–650,
https://doi.org/10.1007/978-1-4613-3485-9_31, 1983.
Melnikov, S. P. and Popov, V. I.: The Distribution and Specific Features of
the Biology of Deepwater Redfish Sebastes mentella (Scorpaenidae) During
Mating in the Pelagial of the Northern Atlantic, J. Ichthyol., 2009,
300–312, https://doi.org/10.1134/S0032945209040031, 2009.
Moat, B. I., Smeed, D. A., Frajka-Williams, E., Desbruyères, D. G., Beaulieu, C., Johns, W. E., Rayner, D., Sanchez-Franks, A., Baringer, M. O., Volkov, D., Jackson, L. C., and Bryden, H. L.: Pending recovery in the strength of the meridional overturning circulation at 26° N, Ocean Sci., 16, 863–874, https://doi.org/10.5194/os-16-863-2020, 2020.
Mulet, S., Rio, M.-H., Etienne, H., Artana, C., Cancet, M., Dibarboure, G., Feng, H., Husson, R., Picot, N., Provost, C., and Strub, P. T.: The new CNES-CLS18 global mean dynamic topography, Ocean Sci., 17, 789–808, https://doi.org/10.5194/os-17-789-2021, 2021.
Nielsen, J. N.: Hydrography of the waters by the Faroe Islands and Iceland
during the cruises of the danish research steamer “Thor” in the summer 1903,
Medd. Komm. f. Havunders. Serie Hydrogr., Bind I Nr. 4, 42 pp., 1904.
Olsen, S. M., Hansen, B., Østerhus, S., Quadfasel, D., and Valdimarsson, H.: Biased thermohaline exchanges with the Arctic across the Iceland–Faroe Ridge in ocean climate models, Ocean Sci., 12, 545–560, https://doi.org/10.5194/os-12-545-2016, 2016.
Orvik, K. A. and Niiler, P.: Major pathways of Atlantic water in the
northern North Atlantic and Nordic Seas toward Arctic, Geophys. Res. Lett.,
29, 1896, https://doi.org/10.1029/2002GL015002, 2002.
Østerhus, S., Sherwin, T., Quadfasel, D., and Hansen, B.: The overflow
transport east of Iceland, Chap. 18, in: Arctic-Subarctic Ocean Fluxes:
Defining the Role of the Northern Seas in Climate, edited by: Dickson, R.
R., Meincke, J., and Rhines, P., Springer Science C Business Media B. V.,
427–441, https://doi.org/10.1007/978-1-4020-6774-7_19, 2008.
Østerhus, S., Woodgate, R., Valdimarsson, H., Turrell, B., de Steur, L., Quadfasel, D., Olsen, S. M., Moritz, M., Lee, C. M., Larsen, K. M. H., Jónsson, S., Johnson, C., Jochumsen, K., Hansen, B., Curry, B., Cunningham, S., and Berx, B.: Arctic Mediterranean exchanges: a consistent volume budget and trends in transports from two decades of observations, Ocean Sci., 15, 379–399, https://doi.org/10.5194/os-15-379-2019, 2019.
Pacariz, S. V., Hátún, H., Jacobsen, J. A., Johnson, C., Eliasen,
S., and Rey, F.: Nutrient-driven poleward expansion of the Northeast
Atlantic mackerel (Scomber scombrus) stock: A new hypothesis, Elem. Sci.
Anth., 4, 105, https://doi.org/10.12952/journal.elementa.000105, 2016.
Perkins, H., Hopkins, T. S., Malmberg, S. A., Poulain, P. M., and
Warn-Varnas, A.: Oceanographic conditions east of Iceland, J. Geophys.
Res.-Oceans, 103, 21531–21542, https://doi.org/10.1029/98JC00890,
1998.
Pyper, B. J. and Peterman, R. M.: Comparison of methods to account for
autocorrelation in correlation analyses of fish data, Can. J. Fish. Aquat.
Sci., 55, 2127–2140, https://doi.org/10.1139/f98-104, 1998.
Rio, M. H., Guinehut, S., and Larnicol, G.: New CNES-CLS09 global mean
dynamic topography computed from the combination of GRACE data, altimetry,
and in situ measurements, J. Geophys. Res., 116,
C07018, https://doi.org/10.1029/2010JC006505, 2011.
Rossby, T., Prater, M. D., and Søiland, H.: Pathways of inflow and
dispersion of warm waters in the Nordic seas, J. Geophys. Res.-Oceans, 114,
C04011, https://doi.org/10.1029/2008JC005073, 2009.
Rossby, T., Flagg, C., Chafik, L., Harden, B., and Søiland, H.: A Direct
Estimate of Volume, Heat, and Freshwater Exchange Across the
Greenland-Iceland-Faroe-Scotland Ridge, J. Geophys. Res.-Oceans, 123,
7139–7153, https://doi.org/10.1029/2018jc014250, 2018.
Sarafanov, A., Falina, A., Mercier, H., Sokov, A., Lherminier, P., Gourcuff,
C., Gladyshev, S., Gaillard, F., and Daniault, N.: Mean full-depth summer
circulation and transports at the northern periphery of the Atlantic Ocean
in the 2000s, J. Geophys. Res., 117, C01014,
https://doi.org/10.1029/2011JC007572, 2012.
Smeed, D. A., McCarthy, G. D., Cunningham, S. A., Frajka-Williams, E., Rayner, D., Johns, W. E., Meinen, C. S., Baringer, M. O., Moat, B. I., Duchez, A., and Bryden, H. L.: Observed decline of the Atlantic meridional overturning circulation 2004–2012, Ocean Sci., 10, 29–38, https://doi.org/10.5194/os-10-29-2014, 2014.
Smeed, D. A., Josey, S. A., Beaulieu, C., Johns, W. E., Moat, B. I.,
Frajka-Williams, E., Rayner, D., Meinen, C. S., Baringer, M. O., Bryden, H.
L., and McCarthy, G. D.: The North Atlantic Ocean Is in a State of Reduced
Overturning, Geophys. Res. Lett., 45, 1527–1533,
https://doi.org/10.1002/2017gl076350, 2018.
Tait, J. B., Lee, A. J., Stefansson, U., and Hermann, F.: Temperature and
salinity distributions and water-masses of the region, Rapp. PV Reun. Cons.
Int. Explor. Mer., 157, 38–149, 1967.
Tsubouchi, T., Våge, K., Hansen, B., Larsen, K. M. H., Østerhus, S.,
Johnson, C., Joìnsson, S., and Valdimarsson, H.: Increased ocean heat
transport into the Nordic Seas and Arctic Ocean over the period 1993–2016,
Nat. Clim. Change, 11, 21–26, https://doi.org/10.1038/s41558-020-00941-3,
2021.
Ullgren, J. E., Darelius, E., and Fer, I.: Volume transport and mixing of the Faroe Bank Channel overflow from one year of moored measurements, Ocean Sci., 12, 451–470, https://doi.org/10.5194/os-12-451-2016, 2016.
Voet, G.: On the Nordic Overturning Circulation, Dissertation zur Erlangung
des Doktorgrades der Naturwissenschaften im Fachbereich Geowissenschaften
der Universität Hamburg, Hamburg, https://citeseerx.ist.psu.edu/document?repid=rep1&type=pdf&doi=a39f14525c76072f3b4f93fc56b32aaa4b8bd06f (last access: 14 August 2023), 98 pp., 2010.
von Storch, H.: Misuses of Statistical Analysis in Climate Research, in:
Analysis of Climate Variability, edited by: von Storch, H. and Navarra, A.,
Springer, Berlin, Heidelberg,
https://doi.org/10.1007/978-3-662-03744-7_2, 1999.
Worthington, E. L., Moat, B. I., Smeed, D. A., Mecking, J. V., Marsh, R., and McCarthy, G. D.: A 30-year reconstruction of the Atlantic meridional overturning circulation shows no decline, Ocean Sci., 17, 285–299, https://doi.org/10.5194/os-17-285-2021, 2021.
Worthington, L. V.: The Norwegian Sea as a mediterranean basin, Deep-Sea
Res. Pt. I, 17, 77–84, https://doi.org/10.1016/0011-7471(70)90088-4, 1970.
Short summary
Based on in situ observations combined with sea level anomaly (SLA) data from satellite altimetry, volume as well as heat (relative to 0 °C) transport of the Iceland–Faroe warm-water inflow towards the Arctic (IF inflow) increased from 1993 to 2021. The reprocessed SLA data released in December 2021 represent observed variations accurately. The IF inflow crosses the Iceland–Faroe Ridge in two branches, with retroflection in between. The associated coupling to overflow reduces predictability.
Based on in situ observations combined with sea level anomaly (SLA) data from satellite...
