Journal cover Journal topic
Ocean Science An interactive open-access journal of the European Geosciences Union
Ocean Sci., 7, 293-304, 2011
https://doi.org/10.5194/os-7-293-2011
© Author(s) 2011. This work is distributed under
the Creative Commons Attribution 3.0 License.
Research article
06 May 2011
Flow and mixing near a glacier tongue: a pilot study
C. L. Stevens1, C. L. Stewart1, N. J. Robinson1,2, M. J. M. Williams1, and T. G. Haskell3 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. A glacier tongue floating in the coastal ocean presents a significant obstacle to the local flow and so influences oceanic mixing and transport processes. Here acoustic Doppler current profiler and shear microstructure observations very near to a glacier tongue side-wall capture flow accelerations and associated mixing. Flow speeds reached around 40 cm s−1, twice that of the ambient tidal flow amplitude, and generated vertical velocity shear squared as large as 10−5 s−2. During the time of maximum flow, turbulent energy dissipation rates reached 10−5 m2 s−3, around three decades greater than local background levels. This is in keeping with estimates of the gradient Richardson Number which dropped to ~1 during maximum flow. Associated vertical diffusivities estimated from the shear microstructure results were substantial, reflecting the influence of the glacier on velocity gradients.

Citation: Stevens, C. L., Stewart, C. L., Robinson, N. J., Williams, M. J. M., and Haskell, T. G.: Flow and mixing near a glacier tongue: a pilot study, Ocean Sci., 7, 293-304, https://doi.org/10.5194/os-7-293-2011, 2011.
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