Climate Dynamics
EPS 231
(Spring 2005)
Instructor:
Eli Tziperman,
Day, time & location: Tue, Thu 11:301; Room: MaxwellDvorkin
G135. Additional optional class time (to be used instead of canceled
lectures, will be announced here and in class if actually used): Fri
13:0014:40, MaxwellDvorkin G135.
Announcements Last updated: May 19, 2005.
The exam will be on Monday, May 23 2005, 10:00. You
can come pick it up from my office then, and return it to me 24
hours later. If you have any conflicts please let me know, and we
can schedule individual times that are 12 days before or after
this date.
Feel free to write or call me with any questions:
Eli Tziperman; eli AT eps.harvard.edu
* Office hours: call/ write.
Matlab code:
THC_3box.m,
elnino_delay_model_1994.m,
THC_winton_1993.m,
circle_map.m,
Homework:
HWENSO1,
HWENSO2,
HWENSO3,
HWENSO4,
HWTHC1,
HWTHC2,
HWTHC3,
HWGLACIAL1,
HWGLACIAL2
Some of the homework require the manipulation of data. You can find
sample relevant data and programs to read and plot it
here,
Climate variability phenomena and mechanisms. From El Nino (37
years), thermohaline circulation variability (decadal to centennial),
DansgaardOeschger events (millennial), Heinrich events (10kyr) and to
glacialinterglacial variability (100 kyr). 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. Students are expected to be
familiar with basic GFD, planetary waves, etc.
A detailed outline of the lectures, and a complete list of reference
materials used in each lecture is available
here.
 Outline and motivation.
 ENSO: main reference is
(Cessi et al., 2001);
additional supporting material may be found
here.
 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
 Westerly wind bursts
 Locking to seasonal cycle
 Atmospheric teleconnections
 Thermohaline circulation; main reference is
(Dijkstra, 2000); additional
supporting material may be found here.
 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)
 Zonally averaged models and closures to 2d models.
 Atmospheric feedbacks
 D/O and Heinrich events: supporting material
may be found here.
 DO:THC flushes vs sea ice changes;
 Heinrich events: bingepurge oscillator, climatic effects,
synchronous collapses
 Glacial cycles: supporting material
may be found here.
 Phenomenology
 Milankovitch forcing
 Energy balance atmosphere
 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
Prerequisites: basic geophysical fluid dynamics.
Homework will be given throughout the course. The best 80% of the
homework will constitute 50% of the final grade. The final exam will
constitute the remaining 50%.

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,
http://gfd.whoi.edu/proceedings/2001/PDFvol2001.html.

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

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