Module Details

The information contained in this module specification was correct at the time of publication but may be subject to change, either during the session because of unforeseen circumstances, or following review of the module at the end of the session. Queries about the module should be directed to the member of staff with responsibility for the module.
Title OCEAN DYNAMICS
Code ENVS332
Coordinator Prof CW Hughes
Earth, Ocean and Ecological Sciences
C.W.Hughes@liverpool.ac.uk
Year CATS Level Semester CATS Value
Session 2019-20 Level 6 FHEQ First Semester 15

Aims

To gain a high level understanding of ocean and atmospheric dynamics:

To understand the background state of the atmosphere and ocean;

To address how tracers spread;

To understand the effects of rotation and how jets and eddies form on a rotating planet;

To understand how waves influence and interact with the ocean circulation;

To understand why there are western boundary currents and gyres in ocean basins;

To understand how topography shapes the deep ocean circulation over the globe.


Learning Outcomes

(LO1) Students will acquire knowledge of key concepts in ocean and atmosphere dynamics.

(LO2) Students will learn to appreciate the approximate nature of theoretical ideas, and the strengths and weaknesses of such ideas as explanations of observed phenomena.

(LO3) Students will develop mathematical skills in scale analysis of differential equations to isolate the essential phenomena.

(LO4) Students will acquire experience in combining quantitative and qualitative understanding of dynamics to give clear explanations of observed phenomena in the ocean and atmosphere.

(LO5) Students will develop an understanding of the factors controllng fluid flows on a range of rotating planets.

(S1) Problem solving skills

(S2) Numeracy


Syllabus

 

Two lectures per week for ten weeks:

Week One: Geography of the atmosphere and ocean - general characteristics to be explained, drivers, heat transport and vertical structure, potential density, introduction to the Taylor-Proudman theorem, importance of vertical velocity.

Week Two: Tracer transport - fluxes, advection and diffusion, mixing, scaling (Peclet number), effects of rotation, constraints in two dimensions (non-divergent flow), role of eddies.

Week Three: Pressure and hydrostatic balance, the non-rotating shallow water equations (including the material derivative), shallow water waves (tides, tsunamis), vertical modes, the importance of vertical velocities.

Week Four: Rotation - the origin of the Coriolis force, Geostrophic balance and vertical velocity, Ekman fluxes and Ekman pumping, coastal upwelling, the rotating shallow water equations, shallow water potential vorticity conservation.

Week Five: Waves - different kinds of waves, derivation of Kelvin wave (vertical modes), dispersion relations, phase and group velocities, introduction to Rossby waves.

Week Six: The full equations of motion, scaling analysis, Taylor-Proudman theorem and thermal wind relations, Rossby number and Reynolds number.

Week Seven: Atmospheric circulation - weather systems and scaling, general circulation and overturning cells, need for jets and eddies, jet streams on Earth and other planets.

Week Eight: Rossby waves - derivation of dispersion relation, underlying physics, typical speeds and scales, link to topography and to western boundary currents.

Week Nine: Ocean gyre theory - Sverdrup balance, adjustment to Sverdrup balance, ways in which Sverdrup balance can break down, idealized gyres and topographic steering at subpolar latitudes.

Week Ten: The Meridional overturning circulation - Stommel-Arons theory and its limitations, link between the MOC and western boundary currents, water mass ages and tracer distributi ons.

Each week's lectures will be accompanied by either a problem sheet to be completed before a workshop class in which solutions and further information will be given, or a practical demonstration to consolidate understanding.


Teaching and Learning Strategies

Teaching Method 1 - Lecture
Description: 10 weeks, with 2 lectures per week, covering the following subjects in each week: Week 1: Geography of the atmosphere and ocean - general characteristics to be explained, drivers, heat transport and vertical structure, potential density, introduction to potential vorticity, typical speeds and length scales of atmospheric and oceanic flows. Week 2: How we can work out the flow of air or water from measurements of pressure, or of sea level and density: The Coriolis force and where it comes from; geostrophy and hydrostatic balance. The importance of vertical velocity. Week 3: The Taylor-Proudman theorem and thermal wind: why winds near the top of the troposphere are mainly to the east. Angular momentum and geostrophy. The structure of atmospheric circulation. Week 4: Tracer transport - fluxes, advection and diffusion, mixing, scaling (Peclet number), effects of rotation, constraints in 2 dimensions (non-di vergent flow), role of eddies. Week 5: The full equations of motion, scaling analysis, Rossby number and Reynolds number. Ekman flux. Shallow water equations and vertical modes. Week 8: Waves and dispersion relations: Shallow water, deep water and Kelvin waves and their appearance in the ocean. Introduction to Rossby waves. Week 9: Rossby waves - derivation of dispersion relation, underlying physics, typical speeds and scales, link to topography and to western boundary currents. Baroclinic instability and the Rennell cell, heat exchange between gyres and across the ACC. Week 10: Ocean gyre theory - Sverdrup balance, adjustment to Sverdrup balance, ways in which Sverdrup balance can break down, idealized gyres and topographic steering at subpolar latitudes. Week 11: The Meridional overturning circulation - Stommel-Arons theory and its limitations, link between the MOC and western boundary currents, water mass ages and tracer distributions.&#x A;
Attendance Recorded: Yes

Teaching Method 2 - Tutorial
Description: Tutorials to be spent working through solutions to problem sets and addressing any difficulties
Attendance Recorded: Yes

Teaching Method 3 - Laboratory Work
Description: Demonstrations of effects of rotation and of stratification.
Attendance Recorded: Yes


Teaching Schedule

  Lectures Seminars Tutorials Lab Practicals Fieldwork Placement Other TOTAL
Study Hours 20

  8

2

    30
Timetable (if known)              
Private Study 120
TOTAL HOURS 150

Assessment

EXAM Duration Timing
(Semester)
% of
final
mark
Resit/resubmission
opportunity
Penalty for late
submission
Notes
Exam There is a resit opportunity. Standard UoL penalty applies for late submission. This is an anonymous assessment. Assessment Schedule (When) :End of semester 1  120 minutes    70       
CONTINUOUS Duration Timing
(Semester)
% of
final
mark
Resit/resubmission
opportunity
Penalty for late
submission
Notes
VITAL online test: Atmosphere and ocean characteristics and scaling There is a resit opportunity. Standard UoL penalty applies for late submission. This is an anonymous assessment. Assessment S  Approximately 1-hour    15       
VITAL online test: Atmosphere and ocean dynamics There is a resit opportunity. Standard UoL penalty applies for late submission. This is an anonymous assessment. Assessment Schedule (When) :Wee  Approximately 1-hour    15       

Recommended Texts

Reading lists are managed at readinglists.liverpool.ac.uk. Click here to access the reading lists for this module.