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| Detailed Reference Information |
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Dethleff, D. and Kempema, E.W. (2007). Langmuir circulation driving sediment entrainment into newly formed ice: Tank experiment results with application to nature (Lake Hattie, United States; Kara Sea, Siberia). Journal of Geophysical Research 112: doi: 10.1029/2005JC003259. issn: 0148-0227. |
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Langmuir circulation (Lc) was generated under freezing conditions in saltwater tank experiments through surface wind stress and cross-waves interacting with subsurface return flow. Fine-grained sediments distributed in the tank prior to frazil crystal formation were aligned in parallel streaks in Lc bottom convergence zones. Downwelling at Lc surface convergence zones aligned floating frazil in wind-parallel rows, and individual crystals rotated on helical paths down to the tank bottom and up again to the surface. The crystals interacted with suspended particles in the water column, and with sediment on the tank bottom, preferentially collecting fine-grained particles and enhancing their entrainment into new ice. Evidence includes higher sediment concentrations in ice and ice-interstitial water (ice pore water) as compared to the tank water. Both tank ice and ice interstitial water contain more silt-sized particles than tank water suspension load and tank bottom sediment. Sand is reduced in the ice, and clay is about the same concentration in all samples. This points to preferential entrainment of fine particles in newly formed ice supported by Lc-driven circulation. Comparable results of Lc-supported ice particle entrainment were found in Lake Hattie. Comparison of ice sediment from tank experiments run with Kara Sea material to ice particles from the natural Kara setting showed both types of ice sediment have very similar grain size distributions and mineralogical compositions. Results from experiments and nature help to better understand the potentially Lc-driven entrainment of sediment into ice formed in shallow freezing waters. |
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Abstract |
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Keywords
Cryosphere, Sea ice, Marine Geology and Geophysics, Marine sediments, processes and transport, Oceanography, General, Analytical modeling and laboratory experiments, Oceanography, Physical, Ice mechanics and air/sea/ice exchange processes (0700, 0750, 0752, 0754), Nonlinear Geophysics, Turbulence (3379, 4568, 7863) |
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Publisher
American Geophysical Union 2000 Florida Avenue N.W. Washington, D.C. 20009-1277 USA 1-202-462-6900 1-202-328-0566 service@agu.org |
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