Flow and mixing around a glacier tongue Flow and Mixing Around a Glacier Tongue : A Pilot Study Craig L. Stevens 1*, Craig L. Stewart 1, Natalie J. Robinson 1,2 , Michael J.M. Williams 1, and Timothy G. Haskell 3 1National Institute for Water and Atmospheric Research (NIWA), Greta Point Wellington, New Zealand ( *
[email protected] ) 2University of Otago, Dunedin, New Zealand 3Industrial Research Ltd. (IRL), Gracefield Lower Hutt, New Zealand November 2010 Deleted: August A revision for Ocean Science Deleted: For submission to 1 Flow and mixing around a glacier tongue Abstract A glacier tongue floating in the coastal ocean presents a significant obstacle to the Deleted: ocean local flow and influences oceanic mixing and transport processes. Here acoustic Doppler Deleted: at current profiler and shear microstructure observations very near to a glacier tongue side- Deleted: show wall capture flow accelerations and associated mixing. Flow speeds reached around Deleted: tidally-induced Deleted: pulses and vortices as twice that of the ambient tidal flow amplitude and generated vertical velocity shear as well as concomitant Deleted: -3 -1 large as 3x10 s . During the maximum flow period turbulent energy dissipation rates Deleted: within the pulses Deleted: three -5 2 -3 reached a maximum of 10 m s , around three decades greater than local background Deleted: times levels. This is in keeping with estimates of the gradient Richardson Number which Deleted: around dropped to ~1. Associated vertical diffusivities estimated from the shear microstructure Deleted: unity Deleted: a results we re higher than expected using existing parameterization, possibly reflecting the Deleted: that Deleted: from proximity of the glacier .