Fall 2013

54-1712

plumb@mit.edu

TR 11 - 1230, 54-1623

There is no set text -- I'll be handing out notes and posting them below -- but some of the material we'll cover can be found in Andrews, Holton, and Leovy,

1: Climatological balances of heat, mass, and angular momentum (and the role of eddies).

Here we establish that the observed departures of the zonal-mean stratosphere from radiative equilibrium could not be sustained without the presence of eddies.

2: Transport of heat, momentum, and PV

(Some additional notes on the Lagrangian theory of eddy transport can be found here).

Discussion of "Modified Lagrangian Mean" theory for the barotropic case can be found in Nakamura & Zhu (2010) (through the end of Section 2c; we'll talk about effective diffusivity later).

Problem Set 1 (due Wed Oct 2).

3: Stratospheric Rossby waves

Here we'll talk about conditions for wave propagation; Rossby wave EP fluxes; and wave breaking.

The classic paper on baroclinic Rossby wave propagation on a beta-plane is Charney & Drazin, J. Geophys. Res. (1961); analysis on a sphere and "refractive index" was presented by Matsuno, J. Atmos. Sci. (1970). Propagation up a vortex with a discrete PV edge is discussed in Esler & Scott, J. Atmos. Sci. (2005) (and references therein).

4: The impact of large-scale waves on the stratosphere.

Solution of the mean state problem, given divF. "Downward control"; the Kuo-Eliassen problem for the transient case. Variability of the winter stratosphere; major warmings.

5: Gravity waves and their role in the middle atmosphere circulation. (N.B.: This is a *.xps file.)

Here we'll talk about how upward propagating internal gravity waves: their propagation characteristics, how they break and thereby drive the pole-to-pole mesospheric circulation (the "Murgatroyd-Singleton" circulation). A fairly recent review is Fritts & Alexander, Rev. Geophys. (2003).

6: Quantifying stratospheric transport

Here we talk about

Effective diffusivity, in this context and for the purely 2D case, was introduced by Nakamura, J. Atmos. Sci. (1996). It was applied to stratospheric data by Haynes & Shuckburgh, J. Geophys. Res. (2000) and Allen & Nakamura, J. Geophys. Res. (2001). The 3D case, in which ultimate mixing is accomplished by vertical diffusion (and the result that it does not matter much how variance is ultimately destroyed, as long as it is done at small scales), is discussed in Liebensperger & Plumb, J. Atmos. Sci. (2004)

Engel et al.,

Stiller et al.,

Garcia et al.,

Prepare a summary of these papers to present to class on Wednesday, Nov 26.

7: The Quasi-biennial oscillation

We'll discuss the theory of the QBO driven by 2 internal gravity waves. Movies of the QBO experiment in the lab can be found on the Kyoto Uni. GFD web site (click on "QBO" and then explore). (Description of the original experiment can be found in: Plumb & McEwan,

8: Stratospheric trace species: distribution and inter-relationships

Here we apply what we have learned about stratospheric transport -- in particular, the dominance of isentropic mixing in the wintertime extratropical stratosphere -- to understand how tracer distributions are controlled, and the significance of "equilibrium slopes" and compact tracer-tracer relationships. A more complete exposition is in Plumb,

*2 Dec 2014*