• Aagaard, K., , A. Foldvik, , and S. R. Hillman, 1987: The West Spitsbergen Current: Disposition and water mass transformation. J. Geophys. Res., 92 , (C4). 37783784.

    • Search Google Scholar
    • Export Citation
  • Bourke, R. H., , A. M. Weigel, , and R. G. Paquette, 1988: The westward turning branch of the West Spitsbergen Current. J. Geophys. Res., 93 , (C11). 1406514077.

    • Search Google Scholar
    • Export Citation
  • Boyd, T. J., , and E. A. D’Asaro, 1994: Cooling of the West Spitsbergen Current: Wintertime observations west of Svalbard. J. Geophys. Res., 99 , (C11). 2259722618.

    • Search Google Scholar
    • Export Citation
  • Cairns, J. L., , and G. O. Williams, 1976: Internal wave observations from a midwater float, 2. J. Geophys. Res., 81 , 19431950.

  • Cokelet, E. D., , N. Tervalon, , and J. G. Bellingham, 2008: Hydrography of the West Spitsbergen Current, Svalbard Branch: Autumn 2001. J. Geophys. Res., 113 , C01006. doi:10.1029/2007JC004150.

    • Search Google Scholar
    • Export Citation
  • Cottier, F. R., , F. Nilsen, , M. E. Inall, , S. Gerland, , V. Tverberg, , and H. Svendsen, 2007: Wintertime warming of an Arctic shelf in response to large-scale atmospheric circulation. Geophys. Res. Lett., 34 , L10607. doi:10.1029/2007GL029948.

    • Search Google Scholar
    • Export Citation
  • Daae, K. L., , I. Fer, , and E. P. Abrahamsen, 2009: Mixing on the continental slope of the southern Weddell Sea. J. Geophys. Res., 114 , C09018. doi:10.1029/2008JC005259.

    • Search Google Scholar
    • Export Citation
  • D’Asaro, E. A., 1984: Wind forced internal waves in the North Pacific and Sargasso Sea. J. Phys. Oceanogr., 14 , 781794.

  • D’Asaro, E. A., , and M. D. Morehead, 1991: Internal waves and velocity fine structure in the Arctic Ocean. J. Geophys. Res., 96 , (C7). 1272512738.

    • Search Google Scholar
    • Export Citation
  • D’Asaro, E. A., , and J. H. Morison, 1992: Internal waves and mixing in the Arctic Ocean. Deep-Sea Res., 39 , S459S484.

  • Desaubies, Y. J. F., 1976: Analytical representation of internal wave spectra. J. Phys. Oceanogr., 6 , 976981.

  • Eckert, E. G., , and T. D. Foster, 1990: Upper ocean internal waves in the marginal ice zone of the northeastern Greenland Sea. J. Geophys. Res., 95 , (C6). 95699574.

    • Search Google Scholar
    • Export Citation
  • Fairall, C. W., , E. F. Bradley, , J. S. Godfrey, , G. A. Wick, , J. B. Edson, , and G. S. Young, 1996: Cool-skin and warm-layer effects on sea surface temperature. J. Geophys. Res., 101 , (C1). 12951308.

    • Search Google Scholar
    • Export Citation
  • Fer, I., 2006: Scaling turbulent dissipation in an Arctic fjord. Deep-Sea Res. II, 53 , (1–2). 7795.

  • Fer, I., 2009: Weak vertical diffusion allows maintenance of cold halocline in the central Arctic. Atmos. Oceanic Sci. Lett., 2 , 148152.

    • Search Google Scholar
    • Export Citation
  • Fer, I., , and A. Sundfjord, 2007: Observations of upper ocean boundary layer dynamics in the marginal ice zone. J. Geophys. Res., 112 , C04012. doi:10.1029/2005JC003428.

    • Search Google Scholar
    • Export Citation
  • Foster, T. D., , and E. G. Eckert, 1987: Fine structure, internal waves, and intrusion in the marginal ice zone of the Greenland Sea. J. Geophys. Res., 92 , (C7). 69036910.

    • Search Google Scholar
    • Export Citation
  • Gammelsrød, T., , and B. Rudels, 1983: Hydrographic and current measurements in the Fram Strait, August 1981. Polar Res., 1 , 115126.

  • Garrett, C. J., , and W. H. Munk, 1972: Space-time scales of internal waves. Geophys. Fluid Dyn., 3 , 225264.

  • Garrett, C. J., , and W. H. Munk, 1975: Space-time scales of internal waves: A progress report. J. Geophys. Res., 80 , 291297.

  • Gascard, J-C., , C. Richez, , and C. Roaualt, 1995: New insights on large-scale oceanography in Fram Strait: The West Spitsbergen Current. Arctic Oceanography, Marginal Ice Zones and Continental Shelves, Geophys. Monogr., Vol. 49, Amer. Geophys. Union, 131–182.

    • Search Google Scholar
    • Export Citation
  • Giles, K. A., , S. W. Laxon, , and A. L. Ridout, 2008: Circumpolar thinning of Arctic sea ice following the 2007 record ice extent minimum. Geophys. Res. Lett., 35 , L22502. doi:10.1029/2008GL035710.

    • Search Google Scholar
    • Export Citation
  • Gregg, M. C., 1989: Scaling turbulent dissipation in the thermocline. J. Geophys. Res., 94 , (C7). 96869698.

  • Gregg, M. C., , and E. Kunze, 1991: Shear and strain in Santa Monica Basin. J. Geophys. Res., 96 , (C9). 1670916719.

  • Gregg, M. C., , T. B. Sanford, , and D. P. Winkel, 2003: Reduced mixing from the breaking of internal waves in equatorial waters. Nature, 422 , 513515.

    • Search Google Scholar
    • Export Citation
  • Holloway, G., , and A. Proshutinsky, 2007: Role of tides in Arctic ocean/ice climate. J. Geophys. Res., 112 , C04S06. doi:10.1029/2006JC003643.

    • Search Google Scholar
    • Export Citation
  • Hunkins, K., 1986: Anomalous diurnal tidal currents on the Yermak Plateau. J. Mar. Res., 44 , 5169.

  • Klymak, J. M., , R. Pinkel, , and L. Rainville, 2008: Direct breaking of the internal tide near topography: Kaena Ridge, Hawaii. J. Phys. Oceanogr., 38 , 380399.

    • Search Google Scholar
    • Export Citation
  • Kowalik, Z., , and A. Y. Proshutinsky, 1993: The Arctic Ocean tides. The Polar Oceans and Their Role in Shaping the Global Environment, Geophys. Monogr., Vol. 85, Amer. Geophys. Union, 137–158.

    • Search Google Scholar
    • Export Citation
  • Kunze, E., , E. Firing, , J. M. Hummon, , T. K. Chereskin, , and A. M. Thurnherr, 2006: Global abyssal mixing inferred from lowered ADCP shear and CTD strain profiles. J. Phys. Oceanogr., 36 , 15531576.

    • Search Google Scholar
    • Export Citation
  • Levine, M. D., 1990: Internal waves under the Arctic pack ice during the Arctic Internal Wave Experiment: The coherence structure. J. Geophys. Res., 95 , (C5). 73477357.

    • Search Google Scholar
    • Export Citation
  • Levine, M. D., , C. A. Paulson, , and J. H. Morison, 1985: Internal waves in the Arctic Ocean: Comparison with lower-latitude observations. J. Phys. Oceanogr., 15 , 800809.

    • Search Google Scholar
    • Export Citation
  • Manley, T. O., 1995: Branching of Atlantic Water within the Greenland-Spitsbergen passage: An estimate of recirculation. J. Geophys. Res., 100 , (C10). 2062720634.

    • Search Google Scholar
    • Export Citation
  • Manley, T. O., , R. H. Bourke, , and K. L. Hunkins, 1992: Near-surface circulation over the Yermak Plateau in northern Fram Strait. J. Mar. Syst., 3 , (1–2). 107125.

    • Search Google Scholar
    • Export Citation
  • McPhee, M. G., , T. Kikuchi, , J. H. Morison, , and T. P. Stanton, 2003: Ocean-to-ice heat flux at the North Pole environmental observatory. Geophys. Res. Lett., 30 , 2274. doi:10.1029/2003GL018580.

    • Search Google Scholar
    • Export Citation
  • Morison, J. H., 1991: Seasonal variations in the West Spitsbergen Current estimated from bottom pressure measurements. J. Geophys. Res., 96 , (C10). 1838118393.

    • Search Google Scholar
    • Export Citation
  • Muench, R. D., , M. G. McPhee, , C. A. Paulson, , and J. H. Morison, 1992: Winter oceanographic conditions in the Fram Strait-Yermak Plateau region. J. Geophys. Res., 97 , (C3). 34693483.

    • Search Google Scholar
    • Export Citation
  • Naveira Garabato, A. C., , K. I. C. Oliver, , A. J. Watson, , and M-J. Messias, 2004a: Turbulent diapycnal mixing in the Nordic Seas. J. Geophys. Res., 109 , C12010. doi:10.1029/2004JC002411.

    • Search Google Scholar
    • Export Citation
  • Naveira Garabato, A. C., , K. L. Polzin, , B. A. King, , K. J. Heywood, , and M. Visbeck, 2004b: Widespread intense turbulent mixing in the Southern Ocean. Science, 303 , 210213.

    • Search Google Scholar
    • Export Citation
  • Nilsen, F., , B. Gjevik, , and U. Schauer, 2006: Cooling of the West Spitsbergen Current: Isopycnal diffusion by topographic vorticity waves. J. Geophys. Res., 111 , C08012. doi:10.1029/2005JC002991.

    • Search Google Scholar
    • Export Citation
  • Osborn, T. R., 1980: Estimates of the local rate of vertical diffusion from dissipation measurements. J. Phys. Oceanogr., 10 , 8389.

  • Padman, L., , and T. Dillon, 1991: Turbulent mixing near the Yermak Plateau during the coordinated Eastern Arctic Experiment. J. Geophys. Res., 96 , (C3). 47694782.

    • Search Google Scholar
    • Export Citation
  • Padman, L., , and S. Erofeeva, 2004: A barotropic inverse tidal model for the Arctic Ocean. Geophys. Res. Lett., 31 , L02303. doi:10.1029/2003GL019003.

    • Search Google Scholar
    • Export Citation
  • Padman, L., , A. J. Plueddemann, , R. D. Muench, , and R. Pinkel, 1992: Diurnal tides near the Yermak Plateau. J. Geophys. Res., 97 , (C8). 1263912652.

    • Search Google Scholar
    • Export Citation
  • Perkin, R. G., , and E. L. Lewis, 1984: Mixing in the West Spitsbergen Current. J. Phys. Oceanogr., 14 , 13151325.

  • Plueddemann, A. J., 1992: Internal wave observations from the Arctic environmental drifting buoy. J. Geophys. Res., 97 , (C8). 1261912638.

    • Search Google Scholar
    • Export Citation
  • Polzin, K. L., , J. M. Toole, , and R. W. Schmitt, 1995: Finescale parameterizations of turbulent dissipation. J. Phys. Oceanogr., 25 , 306328.

    • Search Google Scholar
    • Export Citation
  • Polzin, K. L., , E. Kunze, , J. M. Toole, , and R. W. Schmitt, 2003: The partition of finescale energy into internal waves and subinertial motions. J. Phys. Oceanogr., 33 , 234248.

    • Search Google Scholar
    • Export Citation
  • Quadfasel, D., , J. C. Gascard, , and K. P. Koltermann, 1987: Large-scale oceanography in Fram Strait during the 1984 Marginal Ice-Zone Experiment. J. Geophys. Res., 92 , (C7). 67196728.

    • Search Google Scholar
    • Export Citation
  • Rainville, L., , and P. Winsor, 2008: Mixing across the Arctic Ocean: Microstructure observations during the Beringia 2005 Expedition. Geophys. Res. Lett., 35 , L08606. doi:10.1029/2008GL033532.

    • Search Google Scholar
    • Export Citation
  • Rainville, L., , and R. A. Woodgate, 2009: Observations of internal wave generation in the seasonally ice-free Arctic. Geophys. Res. Lett., 36 , L23604. doi:10.1029/2009GL041291.

    • Search Google Scholar
    • Export Citation
  • Rudels, B., , M. Marnela, , and P. Eriksson, 2008: Constraints on estimating mass, heat and freshwater transports in the Arctic Ocean: An exercise. Arctic-Subarctic Ocean Fluxes: Defining the Role of the Northern Seas in Climate, R. R. Dickson, J. Meincke, and P. Rhines, Eds., Springer Science, 315–341.

    • Search Google Scholar
    • Export Citation
  • Saloranta, T. M., , and P. M. Haugan, 2004: Northward cooling and freshening of the warm core of the West Spitsbergen Current. Polar Res., 23 , 7988.

    • Search Google Scholar
    • Export Citation
  • Sanford, T. B., , E. A. D’Asaro, , E. Kunze, , J. H. Dunlap, , R. G. Drever, , M. A. Kennelly, , M. D. Prater, , and M. S. Horgan, 1993: An XCP user’s guide and reference manual. University of Washington Applied Physics Laboratory Tech. Rep APL-UW TR9309, 120 pp.

    • Search Google Scholar
    • Export Citation
  • Schauer, U., , A. Beszczynska-Möller, , W. Walczowski, , E. Fahrbach, , J. Piechura, , and E. Hansen, 2008: Variations of measured heat flow through the Fram Strait between 1997 and 2006. Arctic-Subarctic Ocean Fluxes: Defining the Role of the Northern Seas in Climate, R. R. Dickson, J. Meincke, and P. Rhines, Eds., Springer Science, 65–85.

    • Search Google Scholar
    • Export Citation
  • Sirevaag, A., , and I. Fer, 2009: Early spring oceanic heat fluxes and mixing observed from drift stations north of Svalbard. J. Phys. Oceanogr., 39 , 30493069.

    • Search Google Scholar
    • Export Citation
  • Thorpe, S. A., 2005: The Turbulent Ocean. Cambridge University Press, 439 pp.

  • Wijesekera, H., , L. Padman, , T. Dillon, , M. Levine, , C. Paulson, , and R. Pinkel, 1993: The application of internal-wave dissipation models to a region of strong mixing. J. Phys. Oceanogr., 23 , 269286.

    • Search Google Scholar
    • Export Citation
  • Zhang, J., , and M. Steele, 2007: Effect of vertical mixing on the Atlantic Water layer circulation in the Arctic Ocean. J. Geophys. Res., 112 , C04S04. doi:10.1029/2006jc003732.

    • Search Google Scholar
    • Export Citation
All Time Past Year Past 30 Days
Abstract Views 0 0 0
Full Text Views 61 61 7
PDF Downloads 64 64 8

Internal Waves and Mixing in the Marginal Ice Zone near the Yermak Plateau

View More View Less
  • 1 Geophysical Institute, University of Bergen, and Bjerknes Centre for Climate Research, Bergen, Norway
  • | 2 University Center in Svalbard, Longyearbyen, Norway
  • | 3 Nansen Environmental and Remote Sensing Center, and Bjerknes Centre for Climate Research, Bergen, Norway
© Get Permissions
Restricted access

Abstract

Observations were made of oceanic currents, hydrography, and microstructure in the southern Yermak Plateau in summer 2007. The location is in the marginal ice zone at the Arctic Front northwest of Svalbard, where the West Spitsbergen Current (WSC) carries the warm Atlantic Water into the Arctic Ocean. Time series of approximately 1-day duration from five stations (upper 520 m) and of an 8-day duration from a mooring are analyzed to describe the characteristics of internal waves and turbulent mixing. The spectral composition of the internal-wave field over the southern Yermak Plateau is 0.1–0.3 times the midlatitude levels and compares with the most energetic levels in the central Arctic. Dissipation rate and eddy diffusivity below the pycnocline increase from the noise level on the cold side of the front by one order of magnitude on the warm side, where 100-m-thick layers with average diffusivities of 5 × 10−5 m2 s−1 lead to heat loss from the Atlantic Water of 2–4 W m−2. Dissipation in the upper 150 m is well above the noise level at all stations, but strong stratification at the cold side of the front prohibits mixing across the pycnocline. Close to the shelf, at the core of the Svalbard branch of the WSC, diffusivity increases by another factor of 3–6. Here, near-bottom mixing removes 15 W m−2 of heat from the Atlantic layer. Internal-wave activity and mixing show variability related to topography and hydrography; thus, the path of the WSC will affect the cooling and freshening of the Atlantic inflow. When generalized to the Arctic Ocean, diapycnal mixing away from abyssal plains can be significant for the heat budget. Around the Yermak Plateau, it is of sufficient magnitude to influence heat anomaly pulses entering the Arctic Ocean; however, diapycnal mixing alone is unlikely to be significant for regional cooling of the WSC.

Corresponding author address: Ilker Fer, Geophysical Institute, University of Bergen, Allégaten 70, N-5007 Bergen, Norway. Email: ilker.fer@gfi.uib.no

Abstract

Observations were made of oceanic currents, hydrography, and microstructure in the southern Yermak Plateau in summer 2007. The location is in the marginal ice zone at the Arctic Front northwest of Svalbard, where the West Spitsbergen Current (WSC) carries the warm Atlantic Water into the Arctic Ocean. Time series of approximately 1-day duration from five stations (upper 520 m) and of an 8-day duration from a mooring are analyzed to describe the characteristics of internal waves and turbulent mixing. The spectral composition of the internal-wave field over the southern Yermak Plateau is 0.1–0.3 times the midlatitude levels and compares with the most energetic levels in the central Arctic. Dissipation rate and eddy diffusivity below the pycnocline increase from the noise level on the cold side of the front by one order of magnitude on the warm side, where 100-m-thick layers with average diffusivities of 5 × 10−5 m2 s−1 lead to heat loss from the Atlantic Water of 2–4 W m−2. Dissipation in the upper 150 m is well above the noise level at all stations, but strong stratification at the cold side of the front prohibits mixing across the pycnocline. Close to the shelf, at the core of the Svalbard branch of the WSC, diffusivity increases by another factor of 3–6. Here, near-bottom mixing removes 15 W m−2 of heat from the Atlantic layer. Internal-wave activity and mixing show variability related to topography and hydrography; thus, the path of the WSC will affect the cooling and freshening of the Atlantic inflow. When generalized to the Arctic Ocean, diapycnal mixing away from abyssal plains can be significant for the heat budget. Around the Yermak Plateau, it is of sufficient magnitude to influence heat anomaly pulses entering the Arctic Ocean; however, diapycnal mixing alone is unlikely to be significant for regional cooling of the WSC.

Corresponding author address: Ilker Fer, Geophysical Institute, University of Bergen, Allégaten 70, N-5007 Bergen, Norway. Email: ilker.fer@gfi.uib.no

Save