Start Submission Become a Reviewer

Reading: The mid-depth circulation of the Nordic Seas derived from profiling float observations

Download

A- A+
Alt. Display

Original Research Papers

The mid-depth circulation of the Nordic Seas derived from profiling float observations

Authors:

G. Voet ,

Institut für Meereskunde, KlimaCampus, University of Hamburg, Bundesstr. 53, 20146 Hamburg, DE
X close

D. Quadfasel,

Institut für Meereskunde, KlimaCampus, University of Hamburg, Bundesstr. 53, 20146 Hamburg, DE
X close

K. A. Mork,

Institute of Marine Research and Bjerknes Centre for Climate Research, Bergen, NO
X close

H. Søiland

Institute of Marine Research and Bjerknes Centre for Climate Research, Bergen, NO
X close

Abstract

The trajectories of 61 profiling Argo floats deployed at mid-depth in the Nordic Seas—the Greenland, Lofoten and Norwegian Basins and the Iceland Plateau—between 2001 and 2009 are analysed to determine the pattern, strength and variability of the regional circulation. The mid-depth circulation is strongly coupled with the structure of the bottom topography of the four major basins and of the Nordic Seas as a whole. It is cyclonic, both on the large-scale and on the basin scale, with weak flow (<1 cms−1) in the interior of the basins and somewhat stronger flow (up to 5 cm s−1) at their rims. Only few floats moved from one basin to another, indicating that the internal recirculation within the basins is by far dominating the larger-scale exchanges. The seasonal variability of the mid-depth flow ranges from less than 1 cms−1 over the Iceland Plateau to more than 4 cms−1 in the Greenland Basin. These velocities translate into internal gyre transports of up to 15 ± 10 × 106 m3 s−1, several times the overall exchange between the Nordic Seas and the subpolar North Atlantic. The seasonal variability of the Greenland Basin and the Norwegian Basin can be adequately modelled using the barotropic vorticity equation, with the wind and bottom friction as the only forcing mechanisms. For the Lofoten Basin and the Iceland Plateau less than 50% of the variance can be explained by the wind.

How to Cite: Voet, G., Quadfasel, D., Mork, K.A. and Søiland, H., 2010. The mid-depth circulation of the Nordic Seas derived from profiling float observations. Tellus A: Dynamic Meteorology and Oceanography, 62(4), pp.516–529. DOI: http://doi.org/10.1111/j.1600-0870.2009.00444.x
  Published on 01 Jan 2010
 Accepted on 10 Mar 2010            Submitted on 10 Jul 2009

References

  1. Aagaard , K. and Coachman , L. K . 1968 . The East Greenland Current north of Denmark Strait. Part I . Arctic 21 ( 3 ), 181 – 200 .  

  2. Aagaard , K . 1970 . Wind-driven transports in the Greenland and Norwegian Seas . Deep-Sea Res . 17 , 281 – 291 .  

  3. Davis , R. E . 1998 . Preliminary results from directly measuring mid-depth circulation in the tropical and South Pacific . J. Geophys. Res . 103 ( C11 ), 24619 – 24639 .  

  4. Gascard , J.-C. and Mork , K. A . 2008 . Climatic Importance of Large-Scale and Mesoscale Circulation in the Lofoten Basin Deduced from Lagrangian Observations. In: Arctic-Subarctic Ocean Fluxes , (eds R. R. , Dickson , J. , Meincke and P. , Rhines ), Springer , Dordrecht , 131 – 143 .  

  5. Gould , W. J . 2005 . From Swallow to Argo—the development of neutrally buoyant floats. Deep-Sea Res . Part 1 52 , 529 – 543 .  

  6. Hansen , B. and Østerhus , S . 2000 . North Atlantic-Nordic Seas exchanges . Prog. Oceanogr 45 , 109 – 208 .  

  7. Hansen , B. and Østerhus , S . 2007 . Faroe Bank Channel Overflow 1995-2005 . Prog. Oceanogr 75 , 817 – 856 .  

  8. Helland-Hansen , B. and Nansen , E 1909 . The Norwegian Sea: Its Physical Oceanography based on Norwegian Researches. Report on Norwegian Fishery and Marine Investigations 11,390 pp. ± 25 plates.  

  9. Holloway , G. , Dupont , E , Golubeva , E. , Hälcicinen , S. , Hunke , E. and co-authors . 2007 . Water properties and circulation in Arctic Ocean models. J. Geophys. Res . 112 ( C4 ), C04503 .  

  10. Isachsen , P. E. , LaCasce , J. H. , Mauritzen , C. and Hälcicinen , S . 2003 . Wind-driven variability of the large-scale recirculating flow in the Nordic Seas and Arctic Ocean . J. Phys. Oceanogr 33 , 2534 – 2550 .  

  11. Jakobsen , P. K. , Ribergaard , M. H. , Quadfasel , D. , Schmith , T. and Hughes , C. W . 2003 . Near-surface circulation in the northern North Atlantic as inferred from Lagrangian drifters: variability from the mesoscale to interannual . J. Geophys. Res . 108 ( C8 ), 3251 .  

  12. Jalcobsson , M. , Cherlcis , N. , Woodward , J. , Coakley , B. and Macnab , R . 2000 . New grid of Arctic bathymetry aids scientists and mapmakers . EOS, Trans. Am. Geophys. Un . 81 ( 9 ), 89 .  

  13. Jónsson , S . 1991 . Seasonal and interannual Variability of Wind Stress Curl Over the Nordic Seas . J. Geophys. Res . 96 ( C2 ), 2649 – 2659 .  

  14. Kalnay , E. , Kanamitsu , M. , Kistler , R. , Collins , W. , Deaven , D. and co-authors . 1996 . The NCEP/NCAR 40-Year Reanalysis Project. B. Am. Meteorol. Soc . 77 ( 3 ), 437 – 472 .  

  15. Killworth , P. D . 1992 . An equivalent-barotropic mode in the fine resolution antarctic model . J. Phys. Oceanogr 22 , 1379 – 1387 .  

  16. Köhl , A . 2007 . Generation and stability of a quasi-permanent vortex in the Lofoten Basin . J. Phys. Oceanogr 37 , 2637 – 2651 .  

  17. Kolstad , E. W . 2008 . A QuikSCAT climatology of ocean surface winds in the Nordic seas: identification of features and comparison with the NCEP/NCAR reanalysis . J. Geophys. Res . 113 , D11106 .  

  18. Lavender , K. V. , Owens , W. B. and Davis , R. E . 2005 . The mid-depth circulation of the subpolar North Atlantic Ocean as measured by subsurface floats. Deep-Sea Res . Part 1 52 , 767 – 785 .  

  19. Lebedev , K. V. , Yoshinari , H. , Maximenko , N. A. and Hacker , P. W . 2007 . YoMaHa’07: Velocity data assessed from trajectories of Argo floats at parking level and at the sea surface . IPRC Tech. Rep . 4 ( 2 ), 16 pp .  

  20. Machín , E , Send , U. and Zenlc , W . 2006 . Intercomparing drifts from RAFOS and profiling floats in the deep western boundary current along the Mid-Atlantic Ridge . Sci. Mar 70 ( 1 ), 1 – 8 .  

  21. Marotzke , J. and Willebrand , J . 1996 . The North Atlantic mean circulation: combining data and dynamics. In: The Warm water sphere of the North Atlantic Ocean (eds W. Krauss et al), Borntraeger , Berlin, Stuttgart , 55 – 90 .  

  22. Mauritzen , C . 1996 . Production of dense overflow waters feeding the North Atlantic across the Greenland-Scotland Ridge. Part 1: evidence for a revised circulation scheme . Deep-Sea Res. Part I 43 , 769 – 806 .  

  23. Mork , K. A. and Slcagseth , Ø . 2005 . Annual Sea Surface Height Variability in the Nordic Seas and Arctic Ocean estimated from simplified dynamics. In: The Nordic Seas: An Integrated Perspective (eds H. Drange , T. Dokken , T. Furevik , R. Gerdes and W. Berger ), Geophys. Monogr. Ser. 158, AGU, Washington DC , 51 – 64 .  

  24. Nøst , O. A. and Isachsen , P. E . 2003 . The large-scale time-mean ocean circulation in the Nordic Seas and Arctic Ocean estimated from simplified dynamics . J. Mar Res . 61 , 175 – 210 .  

  25. Orvik , K. A . 2004 . The deepening of the Atlantic water in the Lofoten Basin of the Norwegian Sea, demonstrated by using an active reduced gravity model . Geophys. Res. Lett . 31 , L01306 .  

  26. Orvilc , K. A. and Niiler , P . 2002 . Major pathways of Atlantic water in the northern North Atlantic and Nordic Seas toward Arctic . Geophys. Res. Lett . 29 , 1986 .  

  27. Orvilc , K. A. , Skagseth , Ø. and Mork , M . 2001 . Atlantic inflow to the Nordic Seas: current structure and volume fluxes from moored current meters, VM-ADCP and SeaSoar-CTD observations, 1995-1999. Deep-Sea Res . Part 1 48 , 937 – 957 .  

  28. Park , J. J. , Kim , K. , King , B. A. and Riser , S . 2005 . An advanced method to estimate deep currents from profiling floats . J. Atmos. Ocean. Tech . 22 , 1294 – 1304 .  

  29. Poulain , P.-M. , Warn-Varnas , A. and Niiler , P. P . 1996 . Near-surface circulation of the Nordic seas as measured by Lagrangian drifters . J. Geophys. Res . 101 ( C8 ), 18237 – 18258 .  

  30. Quadfasel , D. and Käse , R . 2007 . Present-Day Manifestation of the Nordic Seas Overflows. In: Ocean Circulation: Mechanisms and Impacts (eds A. Schmittner , J. C. H. Chiang and S. R. Hemmings ), Geophys. Monogr. Ser. 173, AGU, Washington DC , 75 – 89 .  

  31. Roemmich , D. , Boebel , O. , Desaubies , Y. , Freeland , H. , Kim , K. and co-authors . 1999 . Argo: the global array of profiling floats. In: Observing the Oceans in the 21st Century (eds C. J. Koblinsky and N. R. Smith ), GODAE Project Office and Bureau of Meteorology, Melbourne , 248 – 257 .  

  32. Rossby , T. , Prater , M. D. and Søiland , H . 2009 . Pathways of inflow and dispersion of warm waters in the Nordic seas . J. Geophys. Res . 114 , C04011 .  

  33. Serra , N. , Käse , R. H. , Köhl , A. , Stammer , D. and Quadfasel , D . 2010 . On the low-frequency phase relation between the Denmark Strait and the Faroe-Bank Channel overflows . Tellus 62A .  

  34. Smith , W. H. F. and Sandwell , D. T . 1997 . Global sea floor topography from satellite altimetry and ship depth soundings . Science 277 , 1956 – 1962 .  

  35. Søiland , H. , Prater , M. D. and Rossby , T . 2008 . Rigid topographic control of currents in the Nordic Seas . Geophys. Res. Lett . 35 , L18607 .  

  36. Sutherland , D. A. and Picicart , R. S . 2008 . The east Greenland coastal current: structure, variability, and forcing . Prog. Oceanogr 78 , 58 – 77 .  

  37. Thomson , R. E. and Freeland , H. J . 2003 . Topographic steering of a mid-depth drifter in an eddy-like circulation region south and east of the Hawaiian Ridge . J. Geophys. Res . 108 ( C11 ), 3341 .  

  38. Woodgate , R. A. , Fahrbach , E. and Rohardt , G . 1999 . Structure and transports of the East Greenland Current at 75°N from moored current meters . J. Geophys. Res . 104 ( C8 ), 18059 – 18072 .  

comments powered by Disqus