General Circulation and Climate Dynamics

Meteo 597A: General Circulation and Climate Dynamics

Spring 2019

Sukyoung Lee
Phone: 863-1587
Office: 519 Walker Building

Class: T R, 9:05-10:20, 101 Walker Building

Office hours: By appointment

Description: This course provides theoretical and observational treatments of the atmospheric and oceanic general circulation. The theories covered in this class provide insights into why the observed general circulation takes on the form that it does. Because regional climate is constrained by the general circulation, the theoretical understanding also sheds light onto ongoing climate change and provides us with a tool to form hypotheses, to formulate analyses, and to interpret/evaluate the observed/modeled climate changes. For example, the theories may help us understand questions such as: Why does the Arctic warm faster than the rest of the planet?  Why isn’t Antarctica warming as fast as the Arctic?  Climate models project a weakening of the tropical circulation, but why has the tropical circulation been strengthening over the past several decades?  Is it due to internal variability or due to model deficiencies? Class activities are comprised of lectures, journal article discussion led by students, and a class project which is intended to provide each student with an opportunity to enrich her/his own research interests. The assessments are based on the class participation and the project.

Prerequisites: Meteo 521 (or equivalent courses). Students who do not meet these prerequisites may be dis-enrolled during the first 10-day free add-drop period after being informed in writing by the instructor (see: If you have not completed the listed prerequisites, then please promptly consult with me.

Textbook: Atmospheric and Oceanic Fluid Dynamics. G. K. Vallis, 2006, Cambridge Press. 

Internet materials and links: some of the course materials will be available on ANGEL. 

Course expectations: The course objectives are (1) to introduce a theoretical basis for understanding the general circulation of the atmosphere and ocean, and (2) to use those theories to enhance our understanding of climate variability, climate change, and your own research topic from a general circulation perspective.  The expected outcome for students is to gain the ability (1) to understand journal articles on topics of the general circulation and climate; (2) to utilize the knowledge gained from this class for their own research and/or interest. 

Course content 

  1. Introduction 
  • Goals and scope of the course
  • Observations & some current topics
  •   Basic features of the Atmosphere (Vallis Chapter 11.1, 12.1)
  •   Climate response to greenhouse-gas (GHG) forcing:
  •     Poleward jet shift
  •     Expansion of the Hadley circulation
  •     Polar amplification
  •     Stratosphere-troposphere interaction, including stratospheric ozone influence
  •    Walker circulation trend
    • These topics will be referenced throughout the class as examples of theories to be covered
    • They will be revisited at the end of the semester 
  1. Models for eddy-free overturning circulations (Vallis Chapter 11) 
  • Held-Hou Model of the Hadley Circulation
  • Lindzen-Hou Model of the Hadley Circulation
  • Effect of eddies (non-overturning component)
  • Preview of wave-mean flow interaction
  • More on the effect of eddies 
  1. Simplified equations for oceans and atmosphere  
  • The Shallow-Water Quasi-Geostrophic Equations (Vallis 5.3)
  • Energetics of Quasi-Geostrophy (Vallis 5.6) 
  1. Linear theory of large-scale dynamics: Baroclinic instability  
  • Two-layer baroclinic instability (Vallis 6.6)
  • The Eady Problem (Vallis 6.4) 
  1. Nonlinear theory of large-scale dynamics: baroclinic life cycle  
  • Simmons and Hoskins calculations (1978, 1979, 1980)
  • Held & Phillipps (1987)
  • Thorncroft, Hoskins, & McIntyre (1993) 
  1. Wave-mean flow interaction (Vallis Chapter 7) 
  • Quasi-geostrophic preliminaries
  • The Eliassen-Palm Flux
  • The Transformed Eulerian Mean circulation
  • The Non-acceleration Results 
  1. Zonally averaged Mid-latitude Atmospheric Circulation (Vallis Chapter 12.1-12.7) 
  • Surface westerlies and the maintenance of a barotropic jet
  • Layered Models of the midlatitude circulation
  • A stratified model and the real atmosphere
  • The tropopause and the stratification of the atmosphere
  • Critical Layer Dynamics
  • Diffusivity model vs. baroclinic adjustment
  • Epilogue: Can any of these theories explain the observed equator-to-pole temperature gradient? 
  1. Tropical processes and their impact on the global circulation (week 9-10) 
  • Gill response to isolated heating
  • Rossby wave source
  • Ray-tracing
  • Troposphere-stratosphere exchange
  • Quasi-Biennial Oscillation
  • Equatorial super-rotation
  • Epilogue: Any more insight into the question of the observed equator-to-pole temperature gradient? 
  1. Planetary waves and the Stratosphere (Vallis Chapter 13) 
  • Charney-Drazin theorem 
  1. Revisit of the current topics: discussion on selected papers 
  2. Wind-driven ocean circulations & wrap up (Vallis Chapter 15)  

Assessment Tools 

In accordance with the expectation of the course outcome, the main assessment tools consist of an oral presentation of 

  1. your own research interests and what you hope to learn in this class:
    15-minute power point or equivalent presentation (January 22)
    GUIDELINE: Motivate the research (what it is about, why is it important, and what (& how – if your research is advanced enough) you hope to contribute toward addressing the problem);
    20% of final grade
  2. journal-club style presentation/discussion of a journal article (1/2-class period) and the quality of participation in discussions led by other students:
    Each presentation consists of half class period (35 minutes)
    By Feb. 12, decide on a paper of your choice (please consult with me) and provide me with an electronic copy which I will distribute to the rest of the class.
    GUIDELINE for presenter: It is expected that the presentation provides (1) a clear explanation of the main ideas and results of the article while referencing relevant theories and/or observations; (2) critique the article (e.g., on hypothesis, analysis methods, conclusions) and suggest an alternative approach or implications of the study. Ideas for future extension of the work are welcome. Articles often contain confusing description and/or explanations that are difficult to resolve even after putting reasonable amount of effort to understand them (for example, by looking up previous work, consulting with others….). Please feel free to share such weak spots with the rest of the class as part of the discussion.
    GUIDELINE for participants: Read the paper before the class. Ask questions & make comments. Probing questions/comments are most welcome, but questions aimed at clarifications are also invaluable. Dates: 3/12 and 3/14.
    Some classic and historical papers can be found here:
    30% of final grade
  3. Presentations (4/23 & 4/25) and corresponding written essay (due 4/29) about new research idea(s) that resulted by attending this class; preferably ideas related to your own research interests. For feedback on your essay, please submit your draft by 4/16)
    Each presentation consists of 25 minutes
    GUIDELINE: the oral presentation is expected to include motivation, background, main hypothesis/idea and/or re-interpretation of your previous results, and proposed research approach. Length of essay: single spaced, about 2-3 pages.
    30% of final grade
  4. in-class participation and/or occasional homework
    20% of final grade 

Academic integrity statement  

Students in this class are expected to write up their problem sets individually, and to write their papers in their own words using proper citations.  Class members may work on the problem sets in groups, but then each student must write up the answers separately.  Students are not to copy problem; students may not plagiarize text from papers written by others.  Students who present other people's work as their own will receive at least a 0 on the assignment and may well receive an F or XF in the course.  For information about the Earth and Mineral Sciences Academic Integrity Policy, which this course adopts, please see:

Accommodations for students with disabilities  

The Office of Disability Services ( requests and maintains disability-related documents; certifies eligibility for services; determines academic adjustments, auxiliary aids, and/or services; and develops plans for the provision of academic adjustments, auxiliary aids, and/or services as mandated under Title II of the ADA Amendments Act (ADAAA) of 2008 and Section 504 of the Rehabilitation Act of 1973.  A list of these services is provided at