GFD III , Winter 2019

Professors Jen MacKinnon and Bill Young

T/Th 9:30-10:50, Nierenberg Hall 101


Homework #1 (click on it), due Thursday Jan 17th in class

Course Overview

The goal of SIO212C --- a third course on geophysical fluid dynamics --- is to provide physical oceanography students with the background required to work at the frontier of research on unbalanced processes with an emphasis on upper-ocean and mixed layer dynamics. Some of these were once balanced but have ceased to be so (e.g. frontal instabilities), some were never balanced (e.g. internal waves), and some are nonlinear interactions between the two. These topics are of increasing community interest and are central to many ongoing SIO research projects but are not accommodated in parts I and II of the geophysical fluid dynamics sequence SIO 212. Most of these topics are not covered in any pedagogical textbooks, and students (and PIs!) are left to pick up what they can from individual research papers. Here we hope to put together a systematic treatment, an broad intellectual framework in which to understand many of these hot topic issues. This material is intended primarily for second year and above students who have at least taken the first year Fluids and GFD courses. Other interested scientists at any level are quite welcome to sit in and join the discussion.

Each class will involve a combination of lectures and student led discussion of relevant papers that connect lecture material to areas of active research. The paper associated with each lecture is listed below. Additional reference material of possible interest is listed further down.


  • 1/8: NO CLASS

  • 1/10: Overview of submesoscale processes and dynamics, governing equations, parameter space for the quarter, plan for the class

  • 1/15: Review of basic internal wave equations, dynamics [Paper of the day: tbd…]

  • 1/17: More internal wave basics, propagation, WKB, ray tracing.

  • 1/22: Internal tides: generation, modes, global patterns, power.

  • 1/24, ** 2:30-4pm: Near-inertial waves. Slab model wind generation. Interaction with ambient vorticity field. Global maps, power.

  • 1/29: The internal wave continuum. Garrett-Munk. Triad interactions and energy transfer. Mechanics and patterns of wave breaking. Global patterns and budgets.

  • 1/31: Wave / mean flow interaction.

  • 2/5: Low-frequency flows over topography: internal lee waves and non-propagating form drag. Detailed mechanics and global budgets.

  • 2/7: Other flow interactions with topography. Island and headland wakes, associated stirring, biological hot spots.

  • 2/12: The kinematics of passive scalars and passive vectors. Stirring, mixing, gradient amplification and enhanced dispersion.

  • 2/14: Potential vorticity.

  • 2/19: Quasigeostrophic frontogenesis. Semigeostrophic frontogenesis: balanced frontogenesis --- the Hoskins \& Bretherton model and unbalanced frontogenesis --- Blumen's model.

  • 2/21: Frontogenesis and instabilities continued

  • 2/26: Frictional flows in the mixed layer --- ``turbulent thermal wind'' and frontolysis. Mixed layer restratification by friction.

  • 2/28: Surface mixed layer shenanigans continued

  • 3/5: More near-surface instabilities

  • 3/7: Upside-down version, dynamics and instabilities of the bottom boundary layer.

  • 3/12: Biological implications, guest lecture?

  • 3/14: tbd

Office hours:  contact either professor individually to figure out a good time to stop by.



The classes will involve a combination of formal lectures on the underlying theoretical framework coupled with class discussion and presentation of research papers --- both classic and cutting edge. There will be a few formal homeworks, as we think there are some things you will (later) appreciate having had to derive yourself, and thus understand thoroughly. However befitting a senior graduate student class the majority of the work expected will be a combination of reading assigned cutting edge papers (and coming to class prepared to discuss them), and a modest size term project of flexible nature. There are no written exams.

Homework #1 (click on it), due Thursday Jan 17th in class.



Grades will be based on a combination of written assignments and class participation.

Additional Reference material

coming soon….