Instructor:
Eli Tziperman,
TF: Alex Robel, robel at
fas.harvard.edu
Day, time: Monday 2:304:00, Thursday, 2:304;
Location: Geological Museum, 4th floor, room 418. 24 Oxford St, Cambridge.
Announcements Last updated: February 22, 2013.
Feel free to write or call me with any questions:
Office hours: Eli: Tue 1:303, Thu 12; please write/ call before
stopping by, if possible.
Detailed teaching notes and links to source
materials, Matlab codes and
more
Homework assignments and solutions may be
downloaded here
The basics of climate dynamics, from the feedbacks that maintain the
mean climate to phenomenology and mechanisms of climate variability.
We will cover energy balance models, climate equilibria and stability
with examples from equable (warm) climate to snowball earth. Examples
of climate variability to be covered are El Nino (occurring roughly
every 4 yrs), the thermohaline circulation and its multiple equilibria
and variability (decadal and longer); thermohaline variability as a
possible explanation for the medieval warm period and the little ice
ate (hundreds of years); the DansgaardOeschger warming events
observed in the Greenland ice core (every 1500 yr), Heinrich events
involving massive collapses of ice during glacial times (every
710,000yr), glacialinterglacial variability (100,000 yr), and
equable climate dynamics (50 Myrs). In each case, we will discuss
physical mechanisms and demonstrate them with a hierarchical modeling
approach, from toy models to GCMs. Needed background in nonlinear
dynamics will be covered.
Familiarity with some basic Geophysical Fluid Dynamics (the equivalent
of MIT 12.800, or Harvard EPS 131, EPS 132 or EPS 232), or general
fluid dynamics (e.g., engineering fluid courses at Harvard) will be
assumed. The course may be taken as a sequel to Harvard's Physics of
Climate (EPS 208), or MIT's Climate Physics and Chemistry (12.842),
but can also be taken independently of these courses.
Course homepage: http://www.seas.harvard.edu/climate/eli/Courses/EPS231/2013spring/
First lecture (ppt),
A detailed outline of the lectures, and a complete list of reference
materials used in each lecture is available
here.
 Outline and motivation.
 Basic climate feedbacks. Supporting
material.
 energy balance
 small ice cap instability
 El Nino  Southern Oscillation
(Cessi et al., 2001);
supporting
material.
 Phenomenology: basics: Gill atmosphere; reduced gravity
models, equatorial ocean waves (Dijkstra, 2000),
(Gill, 1982).
 Coupled oceanatmosphere dynamics, demonstrated via the
CaneZebiak model
 Delayed oscillator
 ENSO regimes: fast SST, fast wave, mixed; recharge oscillator:
 Irregularity: chaos
 Irregularity: stochastic forcing, non normal dynamics, optimal
initial conditions and stochastic optimals (section 4, eqns
1114, Tziperman and Ioannou, 2002).
 Westerly wind bursts
 Locking to seasonal cycle
 Atmospheric teleconnections, Rossby ray tracing
 Thermohaline circulation (Dijkstra, 2000);
supporting
material.
 Phenomenology, mixed boundary conditions, Stommel model
 Advective and convective feedbacks; flip flop and loop
oscillations.
 Stability, bifurcations and multiple equilibria
 Stochastic forcing; linear vs nonlinear; non normal dynamics,
noise induced transitions between steady states
 Thermohaline flushes (``deep decoupling'' relaxation
oscillations)
 D/O and Heinrich events: supporting
material.
 DO: THC flushes vs sea ice changes;
 Heinrich events: bingepurge oscillator, climatic effects,
synchronous collapses
 Glacial cycles: supporting material.
 Phenomenology
 Milankovitch forcing
 Ice sheets: mass balance, geometry, parabolic profile.
 Glaciology basics: Glenn's law, basic solutions equilibrium
profiles of ice sheets and ice shelves.
 Simple models of glacial cycles
 Phase locking to Milankovitch forcing
 CO and the ocean carbonate system
 Equable climate supporting
material.
 Equator to pole Hadley cell
 Polar stratospheric clouds
 Hurricane mixing of ocean
 Convective cloud feedback
Homework assignments are 50% of final grade, and a final course
project will constitute the remaining 50%. There is an option to
take this course as a pass/fail with approval of instructor. If
interested, you need to obtain this approval during the first three
weeks of the course.

Cessi, P., Pierrehumbert, R., and Tziperman, E. (2001).
 Lectures on enso, the thermohaline circulation, glacial cycles and
climate basics.
In Balmforth, N. J., editor, Conceptual Models of the Climate.
Woods Hole Oceanographic Institution.

Dijkstra, H. A. (2000).
 Nonlinear physical oceanography.
Kluwer Academic Publishers.

Gill, A. E. (1982).
 AtmosphereOcean Dynamics.
Academic Press, Inc, San Diego, CA, 662pp.

Hartmann, D. (1994).
 Global Physical Climatology.
Academic press, San Diego.

Tziperman, E. and Ioannou, P. J. (2002).
 Transient growth and optimal excitation of thermohaline variability.
J. Phys. Oceanogr., 32(12):34273435.