Dr. Anastasia Romanou: Teaching

The Mixed Layer Under Sea Ice


Overview

Mixing in the oceanic mixed layer typically involves the surface stress provided by the atmospheric wind forcing and the buoyancy forcing related to the thermal exchanges between atmosphere and ocean as well as the precipitation/evaporation mass input. The presence of sea ice insulates the ocean surface from the atmospheric influence but applies a surface stress due to the differential motion of the ice pack relative to the ocean currents below it and imposes a different kind of buoyancy forcing through the fresh water (brine) release during ice melting (ice formation).
Regardless of the origin and the kind of surface forcing, momentum and mass sources/sinks at the surface combined with the turbulence produced within the ocean column (shear production vs. buoyancy destruction) will modify the properties of the ocean column (temperature, salinity, momentum).

Class notes


Computing Facilities

The matlab routines solve for the polar mixed layer using the McPhee parameterization for turbulent mixing (Local Turbulence Model). The data used to force the model were collected during the SHEBA experiment . Two events will be simulated here: a winter event (November 3-13, 1997) and a summer event (July 27-August 3, 1998).

1. README first
2. MATLAB routines (press SHIFT key + left-mouse-button-click to download) for UNIX:

  • A Winter Event

  • A Summer Event

  • MATLAB routines for WINDOWS:
  • A Winter Event

  • A Summer Event


  • Discussion


    References

  • The SHEBA project web page
  • M. G. McPhee, 1999. Parameterization of mixing in the ocean boundary layer. J. of Marine Systems, 21, 55-65.
  • L. H. Kantha and C. A. Clayson, 2000. Small Scale Processes in Geophysical Fluid Flows. Academic Press, pp 888.
  • Peter Wadhams, 2000. Ice in the ocean. Gordon and Breach Science Publishers. pp 351.

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