Journal cover Journal topic
Ocean Science An interactive open-access journal of the European Geosciences Union
Journal topic

Journal metrics

Journal metrics

  • IF value: 2.539 IF 2.539
  • IF 5-year value: 3.129 IF 5-year
    3.129
  • CiteScore value: 2.78 CiteScore
    2.78
  • SNIP value: 1.217 SNIP 1.217
  • IPP value: 2.62 IPP 2.62
  • SJR value: 1.370 SJR 1.370
  • Scimago H <br class='hide-on-tablet hide-on-mobile'>index value: 48 Scimago H
    index 48
  • h5-index value: 32 h5-index 32
Volume 5, issue 4
Ocean Sci., 5, 435–445, 2009
https://doi.org/10.5194/os-5-435-2009
© Author(s) 2009. This work is distributed under
the Creative Commons Attribution 3.0 License.
Ocean Sci., 5, 435–445, 2009
https://doi.org/10.5194/os-5-435-2009
© Author(s) 2009. This work is distributed under
the Creative Commons Attribution 3.0 License.

  26 Oct 2009

26 Oct 2009

Observations of turbulence beneath sea ice in southern McMurdo Sound, Antarctica

C. L. Stevens1, N. J. Robinson1,2, M. J. M. Williams1, and T. G. Haskell3 C. L. Stevens et al.
  • 1National Institute for Water and Atmospheric Research (NIWA), Greta Point Wellington, New Zealand
  • 2University of Otago, Dunedin, New Zealand
  • 3Industrial Research Ltd (IRL), Gracefield, Lower Hutt, New Zealand

Abstract. The first turbulence profiler observations beneath land fast sea ice which is directly adjacent to an Antarctic ice shelf are described. The stratification in the 325 m deep water column consisted of a layer of supercooled water in the upper 40 m lying above a quasi-linearly stratified water column with a sharp step in density at mid-depth. Turbulent energy dissipation rates were on average 3×10−8 m2 s−3 with peak bin-averaged values reaching 4×10−7 m2 s−3. The local dissipation rate per unit area was estimated to be 10 m Wm−2 on average with a peak of 50 m Wm−2. These values are consistent with a moderate baroclinic response to the tides. The small-scale turbulent energetics lie on the boundary between isotropy and buoyancy-affected. This will likely influence the formation and aggregation of frazil ice crystals within the supercooled layer. The data suggest that the large crystals observed in McMurdo Sound will transition from initial growth at scales smaller than the Kolmogorov lengthscale to sizes substantially (1–2 orders of magnitude) greater than the Kolmogorov scale. An estimate of the experiment-averaged vertical diffusivity of mass Kρ yields a coefficient of around 2×10−4 m2s−1 although this increased by a factor of 2 near the surface. Combining this estimate of Kρ with available observations of average and maximum currents suggests the layer of supercooled water can persist for a distance of ~250 km from the front of the McMurdo Ice Shelf.

Publications Copernicus
Download
Citation