Dynamical Oceanography
Overall Course Objectives
General course objectives
This course gives students a general introduction to geophysical fluid dynamics as they pertain to the world’s oceans. The course builds on general fluid dynamics and hydrodynamics introducing key concepts of geophysical fluid dynamics: (1) that they take place on a rotating planet introducing the Coriolis effect, (2) they are often times active in a stratified fluid and (3) gravity and aspect ratio often times sets an asymmetry in vertical and horizontal dynamics.
The course provides students knowledge that can be used both as a platform for more advanced studies of the topic, and as a contribution to their development in ocean engineering, oceanography, and earth system science. The course provides a scientific background to sustainable development goals: 13 climate action and 14 life under water.
See course description in Danish
Learning Objectives
- Describe continuum physics as they apply to generalized fluid dynamics.
- Explain the general features and derivation of the Naiver-Stokes equation.
- Formulate scaling laws such as the Boussinesq approximation and the Rossby number based on physical reasoning.
- Apply scaling rules to describe the primary physical balance governing planetary scale fluid flows in a variety of setting.
- Construct and analyze wave-like solutions to the shallow-water equations and explain how they relate to observed periodic motion in the world’s oceans.
- Describe the physical basis for turbulence closure, Reynolds averaging and eddy viscosity.
- Explain the physics of wind forcing on the ocean (i.e. Ekman layer dynamics) and explain how this relates to the vorticity balance of global circulation.
- Construct and visualize numerical solutions to basin scale features of global ocean circulation (e.g. subtropical gyres).
- Plan, perform and present project work as both a written report and an oral presentation.
Course Content
Content
The course will introduce students to continuum physics and derive the Navier Stokes equations from Newtons laws of motion and 2 theorems of vector calculus. The governing equations for geophysical fluid dynamics follows from these with the incorporation of the Coriolis effect. A series of assumptions and restrictions lead to the shallow water equations which form the basis of the dynamical descriptions covered in the course. Specifically, wave-like solutions to these equations will be examined (Kelvin waves, Rossby waves, Internal gravity waves). Students are introduced to the concept turbulence closure and how this provides a tractable means of incorporating internal fluid friction into these dynamics. Particular attention is given to wind driven dynamics (Ekman transport and Ekman pumping) and how these lead to various descriptions of global wind driven circulation (Sverdup balance, Stommel model, Munk model).
Throughout, the theoretical basis of geophysical fluid dynamics will be illustrated with observations such as sea surface height anomalies from satellites, drift track of argo floats, and mooring timeseries.
Learning sessions are organized as lectures, group exercises and student feedback that are constructively aligned. Class activities involve:
• Lectures covering specific topics, and to prepare students for in class exercises and
group work.
• Problem solving (e.g. filling in some of the mathematical arguments to complete equation derivations).
• Small research exercises to find, analyze and visualize available observations illustrating dynamical processes covered theoretically.
• Plenary presentation and discussion to provide feedback on exercises from both peers and teacher.
Students will also conduct a group project in which they will develop a numerical solution on a global scale to the problem of wind driven surface circulation. Students will present the results of these group projects in a written report and a presentation.
Recommended prerequisites
25302, Descriptive Physical Oceanography (or equivalent) plus advanced undergraduate course in calculus.
Teaching Method
Lectures, computer & analytic exercises, project.
Faculty
Remarks
This course provides students with competences relevant to UN SDGs, particularly #13 (Climate action) and #14 (Life below water)