Barotropic aspects of large-scale atmospheric turbulence

The chapter begins with a phenomenological treatment of the observed atmospheric circulation. It then goes on to discuss how the barotropic model arises as a so-calledbalanced model of the slow, vorticity-driven dynamics, from the more general shallowwater model which also admits inertia-gravity waves. This is important because large-scale atmospheric turbulence exhibits aspects of both balanced and unbalanced dynamics. Because of the first-order importance of zonal flows in the atmospheric general circulation, the large-scale turbulence is highly inhomogeneous, and is shaped by the nature of the interaction between zonal flows and Rossby waves described eloquently by Michael McIntyre as a wave-turbulence jigsaw puzzle. This motivates a review of the barotropic theory of wave, mean-flow interaction, which is underpinned by the Hamiltonian structure of geophysical fluid dynamics.

Theory of tropical moist convection

These lecture notes cover the theory of tropical moist convection. Many simplifications are made along the way, like neglecting rotation and treating the atmosphere as a two-dimensional fluid or even reducing the atmosphere to two columns. We can gain an immense amount of insight into the real atmosphere by studying these toy models, including answers to the following questions: What is the dominant energy balance in the tropical free troposphere; what sets the temperature structure of the tropical free troposphere; what happens to the pulse of heating deposited into the atmosphere by a rain cloud; why does the tropical atmosphere have the relative-humidity pro le that it does; and what sets the amount of energy available to storms?

Dynamical system approaches to climate variability

A tutorial is provided on the application of dynamical systems theory to problems in climate dynamics. We start with the analysis of low-dimensional deterministic dynamical systems using bifurcation theory and provide examples in conceptual climate models.We then proceed to stochastic low-dimensional systems and eventually end with operator-based techniques within ergodic theory. In these notes, we start each section from a climate dynamics problem, motivate the choice of the model to study it, and use dynamical systems analysis to understand the behavior of the model solutions. In each of the chapters, a different phenomenon, a different type of model, and/or a different dynamical system tool will be presented.

Clouds in current and in a warming climate

We see them in our everyday lives. They make skies and sunsets even more beautiful, inspiring painters all over the world. But what are clouds? What are the physical processes occurring within a cloud? Do they all look alike, or are there different types of clouds? Why? Beyond our small human scale, how are clouds distributed at large, planetary scales? How do they couple and interact with the large-scale circulation of the atmosphere? What do the physics of cloud formation tell us about the hydrological cycle, including mean and extreme precipitation, in our current climate and in a warming world? What role do they play in the global energetics of the planet, for instance by reflecting the incoming shortwave radiation from the Sun, and by reducing the outgoing longwave radiation to space, because of their high altitudes and thus cold temperatures? These are the questions that will be addressed in these five lectures.