Articles | Volume 12, issue 2
https://doi.org/10.5194/os-12-545-2016
© Author(s) 2016. This work is distributed under
the Creative Commons Attribution 3.0 License.
the Creative Commons Attribution 3.0 License.
https://doi.org/10.5194/os-12-545-2016
© Author(s) 2016. This work is distributed under
the Creative Commons Attribution 3.0 License.
the Creative Commons Attribution 3.0 License.
Research article
| 
13 Apr 2016
Research article |
| 13 Apr 2016
Biased thermohaline exchanges with the Arctic across the Iceland–Faroe Ridge in ocean climate models
Danish Meteorological Institute, Copenhagen,
Denmark
B. Hansen
Faroe Marine Research Institute, Tórshavn, Faroe
Islands
S. Østerhus
Geophysical Institute, University of Bergen,
Norway
D. Quadfasel
Institute of Oceanography, Universität Hamburg,
Germany
H. Valdimarsson
Marine Research Institute, Reykjavik,
Iceland
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Amelie Driemel, Eberhard Fahrbach, Gerd Rohardt, Agnieszka Beszczynska-Möller, Antje Boetius, Gereon Budéus, Boris Cisewski, Ralph Engbrodt, Steffen Gauger, Walter Geibert, Patrizia Geprägs, Dieter Gerdes, Rainer Gersonde, Arnold L. Gordon, Hannes Grobe, Hartmut H. Hellmer, Enrique Isla, Stanley S. Jacobs, Markus Janout, Wilfried Jokat, Michael Klages, Gerhard Kuhn, Jens Meincke, Sven Ober, Svein Østerhus, Ray G. Peterson, Benjamin Rabe, Bert Rudels, Ursula Schauer, Michael Schröder, Stefanie Schumacher, Rainer Sieger, Jüri Sildam, Thomas Soltwedel, Elena Stangeew, Manfred Stein, Volker H Strass, Jörn Thiede, Sandra Tippenhauer, Cornelis Veth, Wilken-Jon von Appen, Marie-France Weirig, Andreas Wisotzki, Dieter A. Wolf-Gladrow, and Torsten Kanzow
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Bogi Hansen, Karin Margretha Húsgarð Larsen, Hjálmar Hátún, and Svein Østerhus
Ocean Sci., 12, 1205–1220, https://doi.org/10.5194/os-12-1205-2016, https://doi.org/10.5194/os-12-1205-2016, 2016
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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.
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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Short summary
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.
K. Logemann, J. Ólafsson, Á. Snorrason, H. Valdimarsson, and G. Marteinsdóttir
Ocean Sci., 9, 931–955, https://doi.org/10.5194/os-9-931-2013, https://doi.org/10.5194/os-9-931-2013, 2013
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
Cited articles
Årthun, M., Eldevik, T., Smedsrud, L. H., Skagseth, Ø., and Ingvaldsen, R. B.: Quantifying the Influence of Atlantic Heat on Barents Sea Ice Variability and Retreat, J. Clim., 4736–4743, https://doi.org/10.1175/JCLI-D-11-00466.1, 2012.
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, 2013.
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, 2013.
Bitz, C. M., Holland, M. M., Weaver, A. J., and Eby, M.: Simulating the ice-thickness distribution in a coupled climate model, J. Geophys. Res., 106, 2441–2463, 2001.
Born, A., Levermann, A., and Mignot, J.: Sensitivity of the Atlantic ocean circulation to a hydraulic overflow parameterisation in a coarse resolution model: response of the subpolar gyre, Ocean Model., 27, 130–142, 2009.
Boulton, C. A., Allison, L. C., and Lenton, T. M.: Early warning signals of Atlantic Meridional Overturning Circulation collapse in a fully coupled climate model, Nat. Commun., 5, 5752, https://doi.org/10.1038/ncomms6752, 2014.
Childers, K. H., Flagg, C. N., and Rossby, T.: Direct velocity observations of volume flux between Iceland and the Shetland Islands, J. Geophys. Res. Oceans, 119, 5934–5944, 2014.
Danabasoglu, G., Large, W. G., and Briegleb, B. P.: Climate impacts of parameterized Nordic Sea overflows, J. Geophys. Res., 115, C11005, https://doi.org/10.1029/2010JC006243, 2010.
Dickson, R. R., and Brown, J.: The production of North Atlantic Deep Water: Sources, rates, and pathways, J. Geophys. Res., 99, 12319–12341, 1994.
Glessmer, M. S., Eldevik, T., Våge, K., Nilsen, J. E. Ø., and Behrens, E.: Atlantic origin of observed and modelled freshwater anomalies in the Nordic Seas, Nature Geosci., 7, 801–805, 2014.
Guemas, V., Blanchard-Wrigglesworth, E., Chevallier, M., Day, J. J., Déqué, M., Doblas-Reyes, F. J., Fučkar, N. S., Germe, A., Hawkins, E., Keeley, S., Koenigk, T., Salas y Mélia, D., and Tietsche, S.: A review on Arctic sea ice predictability and prediction on seasonal-to-decadal timescales, Q. J. R. Meteorol. Soc., 142, 546–561, https://doi.org/10.1002/qj.2401, 2014.
Guo, C., Ilicak, M., Fer, I., Darelius, E., and Bentsen, M.: Baroclinic Instability of the Faroe Bank Channel Overflow, J. Phys. Oceanogr., 44, 2698–2717, 2014.
Hansen, B. and Østerhus, S.: North Atlantic–Nordic Seas exchanges, Prog. Oceanogr., 45, 109–208, 2000.
Hansen, B. and Østerhus, S.: Faroe bank channel overflow 1995–2005, Prog. Oceanogr., 75, 817–856, 2007.
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, 443–474, 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 FaroeCurrent 1993–2013, Ocean Sci., 11, 743–757, https://doi.org/10.5194/os-11-743-2015, 2015.
Haine, T. W., Curry, B., Gerdes, R., Hansen, E., Karcher, M., Lee, C., Rudels, B., Spreen, G., de Steur, L., Stewart, K. D., and Woodgate, R.: Arctic freshwater export: Status, mechanisms, and prospects, Glob. Plane. Change, 125, 13–35, 2015.
Hazeleger, W., Wang, X., Severijns, C., Ştefănescu, S., Bintanja, R., Sterl, A., Wyser, K., Semmler, T., Yang, S., van den Hurk, B., van Noije, T., van der Linden, E., and van der Wiel, K.: EC-Earth V2. 2: description and validation of a new seamless earth system prediction model, Clim. Dynam., 39, 2611–2629, 2012.
Hermann, F.: The T-S diagram analysis of the water masses over the Iceland-Faroe ridge and in the Faroe Bank Channel, in: Rapp. PV Réun. Cons. Perm. Inter. Exp/or. Mer, 157, 139–149, 1967.
Hurrell, J. W.: Influence of variations in extratropical wintertime teleconnections on Northern Hemisphere temperature, Geophys. Res. Let., 23, 665–668, 1996.
Jónsson, S. and Valdimarsson, H.: Water mass transport variability to the North Icelandic shelf, 1994–2010, ICES J. Mar. Sci., 69, 809–815, 2012.
Kalnay, E., Kanamitsu, M., Kistler, R., Collins, W., Deaven, D., Gandin, L., Iredell, M., Saha, S., White, G., Woollen, J., Zhu, Y., Leetmaa, A., Reynolds, R., Chelliah, M., Ebisuzaki, W., Higgins, W., Janowiak, J., Mo, K. C., Ropelewski, C., Wang, J., Jenne, R., and Joseph, D.: The NCEP/NCAR 40-Year Reanalysis Project, Bull. Amer. Meteor. Soc., 77, 437–471, 1996.
Koenigk, T. and Brodeau, L.: Ocean heat transport into the Arctic in the twentieth and twenty-first century in EC-Earth, Clim. Dynam., 42, 3101–3120, 2014.
Köller, M., Käse, R. H., and Herrmann, P.: Interannual to multidecadal variability and predictability of North Atlantic circulation in a coupled earth system model with parametrized hydraulics, Tellus A, 62, 569–578, 2010.
Lake, I. and Lundberg, P.: Seasonal barotropic modulation of the deep-water overflow through the Faroe Bank Channel, J. Phys. Oceanogr, 36, 2328–2339, 2006.
Latif, M. and Keenlyside, N. S.: A perspective on decadal climate variability and predictability, Deep-Sea Res. Pt. II, 58, 1880–1894, 2011.
Latif, M., Roeckner, E., Mikolajewicz, U., and Voss, R.: Tropical stabilization of the thermohaline circulation in a greenhouse warming simulation, J. Climate, 13, 1809–1813, 2000.
Meincke, J.: The modern current regime across the Greenland-Scotland Ridge, in Structure and development of the Greenland-Scotland Ridge, edited by: Bott, M., Saxov, S., Talwani, M., and Theide, J., Springer, New York, 637–650, 1983.
Meehl, G. A., Goddard, L., Boer, G,. Burgman, R., Branstator, G., Cassou, C., Corti, S., Danabasoglu, G., Doblas-Reyes, F., Hawkins, E., Karspeck, A., Kimoto, M., Kumar, A., Matei, D., Mignot, J., Msadek, R., Pohlmann, H., Rienecker, M., Rosati, T., Schneider, E., Smith, D., Sutton, R., Teng, H., van Oldenborgh, G. J., Vecchi, G., and Yeager, S.: Decadal climate prediction: an update from the trenches, Bull. Am. Meteorol. Soc., 95, 243–267, 2014.
Olsen, S. M. and Schmith, T.: North Atlantic–Arctic Mediterranean exchanges in an ensemble hindcast experiment, J. Geophys. Res., 112, C04010, https://doi.org/10.1029/2006JC003838, 2007.
Olsen, S. M., Hansen, B., Quadfasel, D., and Østerhus, S.: Observed and modelled stability of overflow across the Greenland–Scotland ridge, Nature, 455, 519–522, 2008.
Østerhus, S., Turrrell, W. R., Jónsson, S., and Hansen, B.: Measured volume, heat, and salt fluxes from the Atlantic to the Arctic Mediterranean, Geophys. Res. Lett., 32, L07603, https://doi.org/10.1029/2004GL022188, 2005.
Perkins, H., Hopkins, T. S., Malmberg, S. A., Poulain, P. M., and Warn-Varnas, A.: Oceanographic conditions east of Iceland, J. Geophys. Res. Oc., 103, 21531–21542, 1998.
Rahmstorf, S. and Ganopolski, A.: Long-term global warming scenarios computed with an efficient coupled climate model, Clim. Change, 43, 353–367, https://doi.org/10.1023/A:1005474526406, 1999.
Rhines, P., Häkkinen, S., and Josey, S. A.: Is the oceanic heat transport significant in the climate system?, 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, Dordrecht, Netherlands, 87–110, 2008.
Richter, K., Segtnan, O. H., and Furevik, T.: Variability of the Atlantic inflow to the Nordic Seas and its causes inferred from observations of sea surface height, J. Geophys. Res., 117, C04004, https://doi.org/10.1029/2011JC007719, 2012.
Sandø, A. B., Nilsen, J. E., Eldevik, T., and Bentsen, M.: Mechanisms for variable North Atlantic–Nordic seas exchanges, J. Geophys. Res., 117, C12006, https://doi.org/10.1029/2012JC008177, 2012.
Sterl, A., Bintanja, R., Brodeau, L., Gleeson, E., Koenigk, T., Schmith, T., Semmler, T., Severijns, C., Wyser, K., and Yang, S.: A look at the ocean in the EC-Earth climate model, Clim. Dynam., 39, 2631–2657, 2012.
Stommel, H.: Thermohaline Convection with Two Stable Regimes of Flow, Tellus XIII, 2, 224–230, 1961.
Sun, B. and Wang, H.: Larger variability, better predictability?, Int. J. Climatol., 33, 2341–2351, 2013.
Sutton, R. T. and Hodson, D. L.: Atlantic Ocean forcing of North American and European summer climate, Science, 309, 115–118, 2005
Swaters, G. E.: On the baroclinic instability of cold-core coupled density fronts on a sloping continental shelf, J. Fluid Mech., 224, 361–382, 1991.
Swingedouw, D., Rodehacke, C. B., Olsen, S. M., Menary, M., Gao, Y., Mikolajewicz, U., and Mignot, J.: On the reduced sensitivity of the Atlantic overturning to Greenland ice sheet melting in projections: a multi-model assessment, Clim. Dynam., 44, 3261–3279, https://doi.org/10.1007/s00382-014-2270-x, 2015.
Taylor, K. E., Stouffer, R. J., and Meehl, G. A.: An overview of CMIP5 and the experiment design, Bull. Amer. Meteor. Soc., 93, 485–498, 2012.
Vellinga, M. and Wood, R. A.: Global climatic impacts of a collapse of the Atlantic thermohaline circulation, Clim. Change, 54, 251–267, 2002.
Vihma, T.: Effects of Arctic Sea Ice Decline on Weather and Climate: A Review, Surv. Geophys., 35, 1175–1214, 2014.
Voet, G. and Quadfasel, D.: Entrainment in the Denmark Strait overflow plume by meso-scale eddies, Ocean Sci., 6, 301–310, https://doi.org/10.5194/os-6-301-2010, 2010.
Wang, H., Legg, S. A., and Hallberg, R. W.: Representations of the Nordic Seas Overflows and Their Large Scale Climate Impact in Coupled Models, Ocean Model., 86, 76–92, 2015.
Whitehead, J. A.: Topographic control of oceanic flows in deep passages and straits, Rev. Geophys., 36, 423–440, 1998.
Woodgate, R. A., Weingartner, T. J., and Lindsay, R.: Observed increases in Bering Strait oceanic fluxes from the Pacific to the Arctic from 2001 to 2011 and their impacts on the Arctic Ocean water column, Geophys. Res. Lett., 39, L24603, https://doi.org/10.1029/2012GL054092, 2012.
Yang, S. and Christensen, J. H.: Arctic sea ice reduction and European cold winters in CMIP5 climate change experiments, Geophys. Res. Lett., 39, L20707, https://doi.org/10.1029/2012GL053338, 2012.
Yashayaev, I. and Seidov, D.: The role of the Atlantic Water in multidecadal ocean variability in the Nordic and Barents Seas, Prog. Oceanogr., 132, 68–127, 2015.
Short summary
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.
About half of the warm Atlantic water that enters the Norwegian Sea flows between Iceland and...
