Open AccessWintertime mixed layer measurements at Maud Rise, Weddell Sea
Author(s) -
Sirevaag Anders,
McPhee Miles G.,
Morison James H.,
Shaw William J.,
Stanton Timothy P.
Publication year - 2010
Publication title -
journal of geophysical research: oceans
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.67
H-Index - 298
eISSN - 2156-2202
pISSN - 0148-0227
DOI - 10.1029/2008jc005141
Subject(s) - sea ice , mixed layer , geology , sea ice growth processes , sea ice thickness , atmospheric sciences , heat flux , boundary layer , drift ice , arctic ice pack , geophysics , environmental science , climatology , heat transfer , mechanics , physics
Sea ice plays a crucial role in the exchange of heat between the ocean and the atmosphere, and areas of intense air‐sea‐ice interaction are important sites for water mass modification. The Weddell Sea is one of these sites where a relatively thin first‐year ice cover is constantly being changed by mixing of heat from below and stress exerted from the rapidly changing and intense winds. This study presents mixed layer turbulence measurements obtained during two wintertime drift stations in August 2005 in the eastern Weddell Sea, close to the Maud Rise seamount. Turbulence in the boundary layer is found to be controlled by the drifting ice. Directly measured heat fluxes compare well with previous studies and are well estimated from the mixed layer temperatures and mixing. Heat fluxes are also found to roughly balance the conductive heat flux in the ice; hence, little freezing/melting was observed. The under‐ice topography is estimated to be hydraulically very smooth; comparison with a steady 1‐D model shows that these estimates are made too close to the ice‐ocean interface to be representative for the entire ice floe. The main source and sink of turbulent kinetic energy are shear production and dissipation. Observations indicate that the dynamics of the under‐ice boundary layer are influenced by a horizontal variability in mixed layer density and an increasing amount of open leads in the area.