Climate Dynamics
Spring 2021
FAS course web page for EPS 231
last updated: Monday 29th November, 2021, 13:00

Eli Tziperman (eli@eps.harvard.edu)
Xiaoting Yang (xiaoting_yang@g.harvard.edu)
Day, time:
Tuesday, Thursday, 10:30-11:45
zoom link on canvas, please email Xiaoting or Eli if you don’t have canvas access yet.
Office hours:
Eli: Monday/ Wednesday 1–3, please feel free to write or call me with any questions. Xiaoting: TBA.
Course downloads:
Detailed teaching notes:
including links to source materials, Matlab codes and more


 1 Outline
 2 Syllabus
 3 Requirements

1 Outline

The course covers climate dynamics and climate variability phenomena and mechanisms, and provides hands-on experience running and analyzing climate models, as well as using dynamical system theory tools. The material includes principles of climate dynamics, from feedbacks that maintain different mean climates, to phenomenology and mechanisms of climate variability on multiple time scales. Energy balance and climate equilibria, stability and bifurcations with Snowball Earth as an example. Climate variability: El Nino (roughly 4 yr period), 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 age (hundreds of years); the Dansgaard-Oeschger warming events observed in the Greenland ice cores (every 1500 yr), Heinrich events involving massive collapses of ice during glacial times (every 7-10,000 yr), glacial-interglacial variability (100,000 yr) including ocean, atmospheric and ice dynamics, ocean carbonate chemistry and CO2. Warm climates, from the Pliocene’s (3-5 Myr) permanent El Nino to the Eocene (50 Myr) equable climate, and with lessons to possible surprises in a future warmer climate. In each case, we will discuss physical mechanisms and demonstrate them with a hierarchical modeling approach, from toy models to General Circulation Models. Needed background in nonlinear dynamics will be covered.

The course may be taken as a sequel to MIT’s Climate Physics and Chemistry (12.842) or Harvard’s introduction to climate physics (EPS 208), but can also be taken independently of these courses. Familiarity with some basic Geophysical Fluid Dynamics (the equivalent of MIT 12.800, or Harvard EPS 232) is assumed; (student who took EPS 131 or EPS 132 and are interested in taking the course are requested to contact the instructor).

Course homepage: http://www.seas.harvard.edu/climate/eli/Courses/EPS231/2021spring/

2 Syllabus

A detailed outline of the lectures, and a complete list of reference materials used in each lecture is available here. The course Supporting materials are available here. If accessing from outside campus or via the university wireless network, you will need to connect via the Harvard VPN.

  1. Outline and motivation: First lecture (ppt),
  2. Basic climate feedbacks. Supporting material.
  3. El Nino - Southern Oscillation supporting material.
  4. Thermohaline circulation supporting material.
  5. D/O and Heinrich events: supporting material.
  6. Glacial cycles: supporting material.
  7. Pliocene, 2–5Myr. supporting material.
  8. Equable climate supporting material. Proposed mechanisms:
  9. Data analysis tools for observations and model output (hands-on practice in sections). supporting material.
  10. Review. supporting material.

3 Requirements

Homework assignments every 9–10 days are 50% of final grade, and a final course project will constitute the remaining 50%. The subject of the final project would be discussed in a couple of individual meetings with students during the semester, and would ideally be related to either climate subjects, modeling approaches, nonlinear dynamics methods or data analysis covered in class, and may be related to the research project of the student. The length of the final report should be some 6–10 pages including a few figures, 12pt, in pdf format, and the expected effort is of some 6–8 days of work. Please include an abstract, introduction with the background/ motivation, a methods section including precise details of data sources or model versions/ configuration with relevant links, results, and discussion/ conclusions.

Collaboration policy. We strongly encourage you to discuss and work on homework problems with other students and with the teaching staff. Of course, after discussions with peers, you need to work through the problems yourself and ensure that any answers you submit for evaluation are the result of your own efforts, reflect your own understanding and are written in your own words. In the case of assignments requiring programming, you need to write and use your own code. Please appropriately cite any books, articles, websites, lectures, etc that have helped you with your work.