Clouds cover the majority of Earth’s surface and are essential for regulating the radiative energy budget. This course gives an overview of the turbulent dynamics controlling boundary layers and clouds. It starts from a phenomenological overview of cloud and boundary layer morphologies and leads up to closure theories for turbulence and convection. Topics include similarity theories for boundary layers; mixed-layer models; moist thermodynamics and stability; stratocumulus and trade-cumulus boundary layers; shallow cumulus convection and deep convection; climate change.
Introduction to the fundamental processes governing atmospheric circulations and climate. Starting from an overview of the observed state of the atmosphere and its variation over the past, the course discusses Earth’s radiative energy balance including the greenhouse effect, Earth’s orbit around the Sun and climatic effects of its variations, and the role of atmospheric circulations in maintaining the energy, angular momentum, and water balances, which determine the distributions of temperatures, winds, and precipitation. The focus throughout is on order-of-magnitude physics that is applicable to climates generally, including those of Earth’s past and future and of other planets.
Introduction to the global-scale fluid dynamics of atmospheres, beginning with a phenomenological overview of observed circulations on Earth and other planets and leading to currently unsolved problems. Topics include constraints on atmospheric circulations and zonal winds from angular momentum balance; Rossby wave generation, propagation, and dissipation and their roles in the maintenance of global circulations; Hadley circulations and tropical-extratropical interactions; energy cycle and thermodynamic efficiency of atmospheric circulations. The course focuses on Earth’s atmosphere but explores a continuum of possible planetary circulations and relationships among them as parameters such as the planetary rotation rate change.
Introduction to climate models, from numerical methods for the underlying equations of motion to parameterization schemes for processes such as clouds, sea ice, and land hydrology. The course will move from an overview of modeling concepts and their history to the practice of climate modeling today. It will enable students to design their own model experiments and to evaluate modeling results critically.
Key features of the surface climate can be understood by considering how basic physical balances constrain global atmospheric circulations. This course gives an overview of the physical balances involved and explores some of their implications for maintaining the surface climate: energy balance and its role in controlling temperatures; angular momentum balance and its role in controlling winds; the hydrologic cycle and its role in controlling humidity and aridity; tracer transport and connections to the surface. The relative importance of mean circulations, transient eddies, and stationary eddies in these balances will be discussed, as will be the dynamics of their generation and maintenance. The course gives an overview of the dominant processes that govern the surface climate, with a focus on phenomenology and order-of-magnitude physics that is applicable to climates generally, including those of Earth’s distant past and of other planets.
Understanding the fluid dynamics of the general circulation of the atmosphere is fundamental for understanding how climate is maintained and how it may vary. This course provides an intensive introduction to the principles governing the atmospheric general circulation, reaching from classical models of instabilities in atmospheric flows to currently unsolved problems.
Topics include Rossby waves and barotropic instability; the quasigeostrophic two-layer model and baroclinic instability; conservation laws for wave quantities and wave-mean flow interaction theory; turbulent fluxes of heat and momentum; geostrophic turbulence; genesis of zonal jets. The course focuses on Earth’s atmosphere but treats the circulation of Earth’s atmosphere as part of a continuum of possible planetary circulations.
Introduction to fundamental ideas and techniques of statistical modeling, with an emphasis on conceptual understanding and on the analysis of real data sets. Multiple regression: estimation, inference, model selection, model checking. Regularization of ill-posed and rank-deficient regression problems. Cross-validation. Principal component analysis. Discriminant analysis. Resampling methods and the bootstrap.
Laminar-stability theory as a guide to laminar-turbulent transition. Rayleigh equation, instability criteria, and response to small inviscid disturbances. Discussion of Kelvin-Helmholtz, Rayleigh-Taylor, Richtmyer-Meshkov instabilities and instabilities in geophysical flows. The Orr-Sommerfeld equation, the dual role of viscosity, and boundary-layer stability. Modern concepts such as pseudomomentum conservation laws and nonlinear stability theorems for 2D and geophysical flows. Weakly nonlinear stability theory and phenomenological theories of turbulence.
Introduction to the basic physical balances governing atmospheric circulations and climate. Topics include the angular momentum balance of the atmosphere and how it is maintained; the energy balance, heat transport, and the nature of the atmospheric heat engine; and the hydrologic cycle. The course gives an overview of the dominant processes that govern the surface climate, with a focus on phenomenology and order-of-magnitude physics that is applicable to climates generally, including those of Earth’s distant past and of other planets.
A course on advanced topics in atmosphere and ocean dynamics, leading to current research problems. Topics covered vary from year to year and include geostrophic turbulence, cloud and boundary layer dynamics, principles of global planetary circulations, large-scale ocean dynamics, and tropical atmosphere dynamics.
- Geophysical Turbulence (2003)
- Global Atmospheric Circulations (2004)
- Large-Scale Dynamics of the Atmosphere (2005)
- Principles of Global Planetary Circulations (2006)
- Tropical Atmosphere Dynamics (2007)
- Large-Scale Ocean Dynamics (2008)
- Principles of Planetary Circulations (2009)
- Cloud and Boundary Layer Dynamics (2011, with Joao Teixeira)
Introduction to the global-scale fluid dynamics of the atmosphere, beginning with an analysis of classical models of instabilities in atmospheric flows and leading to currently unsolved problems. We will analyze models of baroclinic instability (the instability mechanism responsible for weather variability in midlatitudes); discuss theories of large-scale waves in the atmosphere; and examine such currently unsolved problems as the modeling of the macro-turbulence of the atmosphere. The course is designed for students in environmental science and planetary science and for applied mathematicians and engineers seeking an introduction to current research topics in atmospheric dynamics.
Topics include: barotropic Rossby waves; the quasigeostrophic two-layer model (potential vorticity, baroclinic instability); wave-mean flow interaction theory (non-acceleration theorem); turbulent fluxes in the extratropical climate; geostrophic turbulence; global-scale tracer transport; Hadley cell dynamics.