Ocean boundary layer turbulence

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• Bethan Wynn’s-Cattanach, Scripps Institution of Oceanography
• Thursday 06 June 2024, 11:30-12:30
• Open Plan Area, Institute for Energy and Environmental Flows, Madingley Rise CB3 0EZ.

If you have a question about this talk, please contact Catherine Pearson.

Observations of diapycnal upwelling and interior exchange along the ocean’s sloping bottom boundary:

Recent theories suggest that deep-ocean upwelling, vital for maintaining the abyssal overturning circulation, is confined to a bottom boundary layer on the ocean’s sloping seafloor. However, direct evidence of near-boundary upwelling and the processes that cause it are lacking. This talk presents findings from a field campaign conducted in a typical continental slope canyon, which focused on directly observing the turbulent processes within the near-boundary region. Using a passive dye release, we observed rapid diapycnal upwelling at a rate approximately 10,000 times higher than the global average needed to sustain the circulation. Long-term observations from moorings suggest that the upwelling was driven by the convective breaking of the internal tide. We also find that three-dimensional processes are crucial, noting adiabatic exchange between the boundary region and the interior at tidal and longer timescales. This exchange re-stratifies the boundary, making mixing efficient and allowing for diapycnal upwelling.

Bio:

Bethan Wynne-Cattanach is a post-doctoral researcher at Scripps Institution of Oceanography in the Multiscale Ocean Dynamics group. She is currently visiting the University of Cambridge as a David Crighton Fellow. Her research focuses on submesoscale and turbulent processes driven by flow-topography interactions and how these lead to water mass transformation. She has been involved in several observational field campaigns, including looking at island wake dynamics during the Flow Encountering Abrupt Topography (FLEAT) Experiment and tidally-driven upwelling as part the Boundary Layer Turbulence and Abyssal Recipes (BLT) Experiment.

This talk is part of the Institute for Energy and Environmental Flows (IEEF) series.

This talk is included in these lists:

• All Talks (aka the CURE list)
• Cambridge Energy Seminars
• Department of Earth Sciences seminars
• Institute for Energy and Environmental Flows (IEEF)
• NanoDTC Energy Materials Talks
• Open Plan Area, Institute for Energy and Environmental Flows, Madingley Rise CB3 0EZ
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