caa a22 4500 605546770 CHVBK 20210128100942.0 cr unu---uuuuu 210128e20150301xx s 000 0 eng 10.1007/s10236-014-0799-1 doi (NATIONALLICENCE)springer-10.1007/s10236-014-0799-1 Behavior and mixing of a cold intermediate layer near a sloping boundary [Elektronische Daten] [Frédéric Cyr, Daniel Bourgault, Peter Galbraith] As in many other subarctic basins, a cold intermediate layer (CIL) is found during ice-free months in the Lower St. Lawrence Estuary (LSLE), Canada. This study examines the behavior of the CIL above the sloping bottom using a high-resolution mooring deployed on the northern side of the estuary. Observations show successive swashes/backwashes of the CIL on the slope at a semi-diurnal frequency. It is shown that these upslope and downslope motions are likely caused by internal tides generated at the nearby channel head sill. Quantification of mixing from 322 turbulence casts reveals that in the bottom 10 m of the water column, the time-average dissipation rate of turbulent kinetic energy is 𝜖 10 m = 1.6×10−7Wkg−1, an order of magnitude greater than found in the interior of the basin, far from boundaries. Near-bottom dissipation during the flood phase of the M2 tide cycle (upslope flow) is about four times greater than during the ebb phase (downslope flow). Bottom shear stress, shear instabilities, and internal wave scattering are considered as potential boundary mixing mechanisms near the seabed. In the interior of the water column, far from the bottom, increasing dissipation rates are observed with both increasing stratification and shear, which suggests some control of the dissipation by the internal wave field. However, poor fits with a parametrization for large-scale wave-wave interactions suggests that the mixing is partly driven by more complex non-linear and/or smaller scale waves. Springer-Verlag Berlin Heidelberg, 2015 Turbulence nationallicence Boundary mixing nationallicence Cold intermediate layer nationallicence Lower St. Lawrence Estuary nationallicence Internal tides nationallicence Internal wave nationallicence Shear instabilities nationallicence Bottom shear stress nationallicence Cyr Frédéric Institut des sciences de la mer de Rimouski, Université du Québec à Rimouski, Rimouski, Québec, Canada aut Bourgault Daniel Institut des sciences de la mer de Rimouski, Université du Québec à Rimouski, Rimouski, Québec, Canada aut Galbraith Peter Maurice Lamontagne Institute, Department of Fisheries and Oceans Canada, Mont-Joli, Québec, Canada aut Ocean Dynamics Springer Berlin Heidelberg 65/3(2015-03-01), 357-374 1616-7341 65:3<357 2015 65 10236 https://doi.org/10.1007/s10236-014-0799-1 text/html Onlinezugriff via DOI BK010053 XK010053 XK010000 Metadata rights reserved Springer special CC-BY-NC licence nationallicence 1 research-article jats NATIONALLICENCE NATIONALLICENCE NL-springer NATIONALLICENCE 856 40 https://doi.org/10.1007/s10236-014-0799-1 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Cyr Frédéric Institut des sciences de la mer de Rimouski, Université du Québec à Rimouski, Rimouski, Québec, Canada aut NATIONALLICENCE 700 1- Bourgault Daniel Institut des sciences de la mer de Rimouski, Université du Québec à Rimouski, Rimouski, Québec, Canada aut NATIONALLICENCE 700 1- Galbraith Peter Maurice Lamontagne Institute, Department of Fisheries and Oceans Canada, Mont-Joli, Québec, Canada aut NATIONALLICENCE 773 0- Ocean Dynamics Springer Berlin Heidelberg 65/3(2015-03-01), 357-374 1616-7341 65:3<357 2015 65 10236