Woods Hole Oceanographic Institution

Claudia Cenedese

»Cyclone and anticyclone asymmetry in a rotating stratified fluid over bottom topography
»Eddy-shedding from a boundary current around a cape over a sloping bottom
»Stability of a buoyancy-driven coastal current at the shelf break
»Laboratory experiments on mesoscale vortices colliding with a seamount
»A dense current flowing down a sloping bottom in a rotating fluid
»A laboratory model of thermocline depth and exchange fluxes across circumpolar fronts
»Laboratory experiments on a mesoscale vortex colliding with topography of varying geometry in a rotating fluid
»Variability of Antarctic bottom water flow into the North Atlantic
»Laboratory experiments on mesoscale vortices interacting with two islands
»Laboratory experiments on eddy generation by a buoyant coastal current flowing over variable bathymetry
»How entraining density currents influence the stratification in a one-dimensional ocean basin
»Laboratory observations of enhanced entrainment in dense overflows in the presence of submarine canyons and ridges
»Laboratory experiments on mesoscale vortices colliding with an island chain
»Mixing in a density-driven current flowing down a slope in a rotating fluid
»Variations in ocean surface temperature due to near surface flow: straining the cool skin layer
»Laboratory experiments on the interaction of a buoyant coastal current with a canyon: application to the East Greenland Current
»A new parameterization for entrainment in overflows
»The relationship between flux coefficient and entrainment ratio in density currents
»Impact of fjord dynamics and glacial runoff on the circulation near Helheim Glacier
»Laboratory experiments on two coalescing axisymmetric turbulent plumes in a rotating fluid
»Entrainment and mixing dynamics of surface-stress-driven stratifi ed flow in a cylinder
»Downwelling in Basins Subject to Buoyancy Loss
»A Geostrophic Adjustment Model of two Buoyant Fluids
»Offshore Transport of Shelf Waters through Interaction of Vortices with a Shelfbreak Current
»Laboratory experiments and observations of cyclonic and anticyclonic eddies impinging on an island
»Seasonal variability of submarine melt rate and circulation in an East Greenland fjord
»The Dispersal of Dense Water Formed in an Idealized Coastal Polynya on a Shallow Sloping Shelf
»Entrainment in two coalescing axisymmetric turbulent plumes
»Impact of periodic intermediary flows on submarine melting of a Greenland glacier
»Dynamics of Greenland’s glacial fjords and their role in climate
»Gravity Current Propagation Up a Valley
»On the collision of sea breeze gravity currents

Cenedese C., Downwelling in Basins Subject to Buoyancy Loss, J. Phys. Oceanogr., 42, 2012

Recent observational, theoretical, and modeling studies all suggest that the upper part of the downwelling limb of the thermohaline circulation is concentrated in strong currents subject to buoyancy loss near lateral boundaries. This is fundamentally different from the traditional view that downwelling takes place in regions of deep convection. Even when resolving the buoyant boundary currents, coarse-resolution global circulation and climate models rely on parameterizations of poorly known turbulent mixing processes. In this  study, the first direct measurements of downwelling occurring within a basin subject to buoyancy loss are obtained. Downwelling is observed near the basin’s vertical wallwithin the buoyant boundary current flowing cyclonically around the basin. Although the entire basin is cooled, large-scale mean downwelling is absent in the basin interior. Laboratory rotating experiments are conducted to explicitly resolve the turbulent mixing due to convective plumes and the baroclinic eddies generated by the boundary current, and to  identify where downwelling takes place. Small vertical velocities can be measured more reliably in the laboratory than in many numerical calculations, whereas the measurement of these small vertical velocities is still a challenge for field experiments. Downwelling is observed near the vertical wall within a boundary layer with a thickness that scales with the baroclinic Rossby radius of deformation, consistent with the dynamical balance proposed by a previous numerical study. Hence, downwelling in the Labrador Sea and Lofoten Basin cyclonic boundary currentsmay be concentrated in a baroclinic Rossby radius of deformation thick boundary layer in regions with large eddy generation.

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