THIS IS A BOOK ON THE DYNAMICS OF THE ATMOSPHERE AND OCEAN, with an emphasis on the fundamentals and on the large-scale circulation. By ‘large-scale’ I mean scales between that of the weather (a few hundred kilometres in the atmosphere and a few tens of kilometres in the ocean, which indeed has its own weather) and the global scale. My focus is our own planet Earth, for that is where we live, but the principles and methodology used should be appropriate for the study of the atmospheres and oceans of other planets. And even if we stay at home, I try to take the reader on a journey — from the most basic and classical material to the frontiers of knowledge.

The book is written at a level appropriate for advanced undergraduate or graduate courses; it is also meant to be a useful reference for researchers, and some aspects of the book have the nature of a research monograph. Prior knowledge of fluid dynamics is helpful but is not a requirement, for the fluid equations are introduced in the first chapter. Similarly, some knowledge of thermodynamics will ease the reader's path, but is not essential. On the other hand, the reader is assumed to have a working knowledge of vector calculus and to know what a partial differential equation is.

Atmospheric and oceanic fluid dynamics (aofd) is both pure and applied. It is a pure because it involves some of the most fundamental and unsolved problems in fluid dynamics — problems in turbulence and wave–mean flow interaction, in chaos and predictability, and in the general circulation itself. It is applied because the climate and weather so profoundly affect the human condition, and the practice of weather forecasting is a notable example of a successful (yes it is) applied science. The field is also broad, encompassing such subjects as the general circulation, instabilities, gyres, boundary layers, waves, convection and turbulence. My goal in this book is to present a coherent selection of these topics so that the reader will gain a solid grounding in the fundamentals, motivated by and with an appreciation for the problems of the real world. The book is primary a theoretical one, but in a number of places observations are used to illustrate the dynamics and define the problems.