PHYS/ASTR Colloquium: "Turbulent Mixing in the Upper Ocean Transition Layer" - Prof. Alexis Kaminski (U.C. Berkeley)

San Francisco State University

Physics & Astronomy Colloquium Series

Monday, February 26, 2024

Thornton Hall 411, 3:30 PM

"Turbulent mixing in the upper ocean transition layer"

Prof. Alexis Kaminski (U.C. Berkeley)

Abstract: The ocean surface boundary layer (OSBL) is a key part of the global climate system: it mediates the exchange of heat, momentum, carbon, and other key tracers between the atmosphere and ocean interior and plays an important role in the ocean's primary productivity by controlling access to nutrients and light. However, models often struggle to capture this layer accurately, due in part to errors in the parameterization of the small-scale turbulent physics driving mixing and entrainment. 

One region of the OSBL that has received relatively little attention is the strongly-sheared, strongly-stratified transition layer (TL) separating the well-mixed layer at the surface from the stably-stratified ocean interior. The TL can theoretically support a variety of waves and instabilities, each of which can lead to different mixing behaviors. In this talk, I will present observations of the North Pacific TL from fall 2018, and describe some of the key fluid dynamical processes at play. Using complementary idealized numerical simulations, I will describe recent work aimed at better interpreting these measurements and describing the turbulent entrainment in this layer.