Large-Scale Dynamics of the Atmosphere

This course provides an introduction to the global-scale fluid dynamics of the atmosphere, beginning with an analysis of classical models of instabilities in atmospheric flows and leading to currently unsolved problems. We will analyze models of baroclinic instability (the instability mechanism responsible for weather variability in midlatitudes); discuss theories of large-scale waves in the atmosphere; and examine such currently unsolved problems as the modeling of the macro-turbulence of the atmosphere. The course is designed for students in environmental science or planetary science and for applied mathematicians or engineers seeking an introduction to current research topics in atmospheric dynamics.

Topics include: barotropic Rossby waves; the quasigeostrophic two-layer model (potential vorticity, baroclinic instability); wave-mean flow interaction theory (non-acceleration theorem); turbulent fluxes in the extratropical climate; geostrophic turbulence; global-scale tracer transport; Hadley cell dynamics.

This course complements and can be taken concurrently with ESE/Ge 152c.

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Instructor: Tapio Schneider

Prerequisites: Basic knowledge of fluid dynamics is helpful.

Grading: Homework 40%; class presentation of research paper 60%. (No exams.)

Texts: Excerpted background readings will be assigned from the following texts (on reserve in SFL library):

Held, I. M., 2000: The General Circulation of the Atmosphere. Lecture Notes, Woods Hole Oceanographic Institution. (Available online.)

Holton, J. R., 1992: An Introduction to Dynamic Meteorology. 3rd ed. Academic Press.

Lorenz, E. N., 1967: The Nature and Theory of the General Circulation of the Atmosphere. WMO Publication, Vol. 218.

Palmen, E., and C. W. Newton, 1969: Atmospheric Circulation Systems: Their Structure and Interpretation. Academic Press.

Pedlosky, J., 1987: Geophysical Fluid Dynamics. 2nd ed. Springer-Verlag.

Salmon, R., 1998: Lectures on Geophysical Fluid Dynamics. Oxford University Press.

Syllabus:

April 3

General circulation of the atmosphere: nature of the problem. Qualitative inferences from the angular momentum budget: zonal mean winds and the role of vorticity mixing in the maintenance of the mean surface winds.
Reading: Lorenz, Chapters I and III; Held, Lecture 1; Palmen and Newton, Chapter 1.

April 10

Barotropic flow on a beta-plane: Rossby waves, momentum fluxes, instability theory.
Reading: Held, Lecture 2.

April 17

Stability of barotropic flow: Stability criteria, equilibration, confined turbulent mixing.
Reading: Drazin and Reid, Hydrodynamic Stability, Chapter 4 (Cambridge UP, 1981).

April 24

Shallow-water model: Potential vorticity, potential vorticity flux, wave-mean flow interaction.
Reading: Salmon, Chapters 2.3–2.5; Held, Lecture 3.

May 1

Quasigeostrophic two-layer model I: Baroclinic instability.
Reading: Holton, Chapter 8; Salmon, Chapters 2.12–2.15.

May 8

Quasigeostrophic two-layer model II: Heat fluxes, momentum fluxes, mass fluxes.
Reading: Phillips (1956); Held, Lecture 4.

May 15

Baroclinic instability in continuously stratified flow: Eady model, Charney model. Dynamics in isentropic coordinates.
Reading: Pedlosky, Chapters 7.6–7.8; Hoskins et al. (1985).

May 22

Mass transport circulation of the atmosphere: relationship to turbulent eddy fluxes; turbulent diffusion.
Reading: Held, Lecture 5; Held and Schneider (1999).

May 29

Hadley cell dynamics.
Reading: Held and Hou (1980); James, An Introduction to Circulating Atmospheres, Chapter 4 (Cambridge UP, 1994).