Graduate; Spring

*Spring '14: Lectures TR 11-1230, Rm 54-823*

*(Class meets with 12.810)*

Prereq.: *12.003*

Units: 3-0-9

*Instructor*: Alan Plumb, 54-1712, x3-6281, plumb@mit.edu

Assessment will be based on:

- Problem sets (one every 2 weeks) (60% of grade)

- A final exam (40%).

There is no set text for the class. Formal class notes will be handed out, and made available on this page. Reference to published source material will be made as appropriate. The text we shall reference most frequently is: Holton, J.R.,

Overview of the observed global atmosphere

Theory of the axisymmetric Hadley circulation

Background material on the Boussinesq approximation

A broad (but not very deep) discussion of Hadley cell dynamics can be found in Marshall & Plumb,

Lindzen,

James,

Vallis,

Later in the class, we will address limitations of this zonally symmetric theory as a model of the real world; specifically, eddies play a significant role in the real atmosphere.

Internal gravity waves

Background material on pressure coordinates.

Background material on dispersive and nondispersive waves. The movie clip showing a propagating wave packet, and illustrating the distinction between phase and group velocity, is here. It shows a Gaussian packet about 7 wavelengths wide of small-amplitude surface waves, with carrier wavenumber k = 1/D, on deep water of mean depth D.]

Gill,

Lindzen,

Holton,

Movies of the "St Andrew's Cross" demonstrations in the lab can be found on the Kyoto Uni. GFD web site (click on "Internal Gravity Wave" and then explore). A numerical simulation by Dale Durran (U. Washington) of the "St Andrews' cross" (with a nice zoom-in, showing velocities) can be found here.

There is a large body of literature on mountain waves; some recent examples can be found in the bibliography on Dale Durran's web site.

I: Large-scale flow, potential vorticity and Rossby waves in a shallow water system..

Here are some notes on the shallow water equations.

II: Rossby waves in the atmosphere.

Holton,

The movie clip of the lab Rossby wave demonstration can be found here. A comprehensive presentation of a similar experiment -- the experimental setup, theory, and results -- from the Weather in a Tank project can be found here.

Instability of the zonal flow; genesis of midlatitude storms

This topic is covered in many GFD and atmospheric dynamics texts, e.g., Holton, Chapter 8.

It is difficult to find source material for wave conservation and the stability constraint that does not go much deeper than we do. The Charney-Stern stability theorem was introduced by Charney & Stern,

The original presentation of the "Eady problem" is Eady,

John Marshall's baroclinic instability movie (from 12.307) can be found here. Movies of baroclinic waves (in 3 different regimes) can be found on the Kyoto Uni. GFD web site.

Lorenz,

Climatology of the tropics (slideshow)

Equatorial waves; response to stationary localized forcing: the Gill model; the Walker circulation and monsoons

El Nino and the Southern Oscillation (slideshow)

Much of what we will discuss (except for details of the Gill model) is covered in Holton, Chapter 11. The early definitive study of equatorial waves is by Matsuno,

The "Gill model" of the atmospheric response to localized tropical heating was introduced by Gill,

NOAA has a usfeul and comprehensive web page on many aspects of ENSO, both general and current. The presentation (pdf or ppt) on current status is available from the Climate Prediction Center of the National Weather Service (choose "Weekly ENSO update", pdf or ppt).

Role of Eddies in the General circulation

Discussion of how the extratropical mean state responds to baroclinic eddy fluxes, including how the impact of eddies on the upper tropospheric zonal flow depends on thermal adjustment rates and surface friction, can be found in Robinson,

Problem Set 2 Internal gravity waves (due 20 March). Sample answers

Problem Set 3 Vorticity and Rossby waves (due 17 April;

Problem Set 4 Waves, fluxes and stability (due 8 May).Sample answers

*Alan Plumb*

*Last updated 2014 May 16*