To close the abyssal overturning circulation, dense bottom waters that form around Antarctica have to become lighter by mixing with lighter water above. Recent theoretical work suggested that bottom-enhanced turbulent mixing drives strong upslope flows across density surfaces along rough ocean topography. However, it remains an open question what physics drives the bottom-enhanced turbulent mixing. Here we present a combination of novel observations and numerical results that (1) support the theoretical hypothesis and (2) provide insights on the physics of bottom-enhanced ocean turbulence. The observations were collected as part of the Bottom Boundary Layer Turbulence (BLT) experiment in the Rockall Trough and consists of a combination of tracer release and turbulence measurements. A fluorescent tracer released right above the sloping boundary of the trough is shown to rise rapidly across density surfaces. The turbulence measurements document the characteristics of the turbulent processes that drive this diapycnal flow. Idealized numerical simulations of a tidal flow impinging over a sloping topography are then used to describe the turbulence physics and its characteristics. The presentation will conclude by discussing the implications of these results for the global abyssal ocean circulation.

28 Oct 2022
9am - 10am
Where
Zoom
Speakers/Performers
Xiaozhou Ruan
Boston University
Organizer(S)
Department of Ocean Science
Contact/Enquiries

Julian Mak at jclmak@ust.hk

Payment Details
Audience
Language(s)
English
Other Events
21 Jun 2024
Seminar, Lecture, Talk
IAS / School of Science Joint Lecture - Alzheimer’s Disease is Likely a Lipid-disorder Complication: an Example of Functional Lipidomics for Biomedical and Biological Research
Abstract Functional lipidomics is a frontier in lipidomics research, which identifies changes of cellular lipidomes in disease by lipidomics, uncovers the molecular mechanism(s) leading to the chan...
24 May 2024
Seminar, Lecture, Talk
IAS / School of Science Joint Lecture - Confinement Controlled Electrochemistry: Nanopore beyond Sequencing
Abstract Nanopore electrochemistry refers to the promising measurement science based on elaborate pore structures, which offers a well-defined geometric confined space to adopt and characterize sin...