ATMOSPHERIC AND OCEANIC FLUID DYNAMICS – Fundamentals and Large-scale Circulation

Is a book on the fluid dynamics of the atmosphere and ocean, with an emphasison the fundamentals and on the large-scale circulation, the latter meaning flowsfrom the scale of the first deformation radius (a few tens of kilometres in the ocean,several hundred kilometres in the atmosphere) to the global scale. The book is primarily textbook; it is designed to be accessible to students and could be used as a text for graduatecourses. It may be also useful as an introduction to the field for scientists in other areas anas a reference for researchers in the field, and some aspects of the book have the flavour ofa research monograph.Atmospheric and oceanic fluid dynamics (AOFD) is fascinating field, and simultaneouslyboth pure and applied. It is a pure field because it is intimately tied to some of the mostfundamental and unsolved problems in fluid dynamics — problems in turbulence and wavemeanflow interaction,problems in chaos and predictability, and problems in the generalcirculation itself. Yet it is applied because the climate and weather so profoundly affect thehuman condition, and so a great deal of effort goes into making predictions — indeed thepractice of weather forecasting is a remarkable example of a successful applied science, inspite of the natural limitations to predictability that are now reasonably well understood.The field is plainly important, for we live in the atmosphere and the ocean covers abouttwo-thirds of the Earth. It is also very broad, encompassing such diverse topics as the generalcirculation, gyres, boundary layers, waves, convection and turbulence. My goal in this bookis present a coherent selection of these topics, concentrating on the foundations but withoutshying away from the boundaries of active areas of research — for a book that limits itself towhat is absolutely settled would, I think, be rather dry, a quality best reserved for martinisand humour. AOFD is closely related to the field of geophysical fluid dynamics (GFD). The latter cabe, depending on one's point of view, both a larger and a smaller field than the former. Itis larger because GFD, in its broadest meaning, includes not just the fluid dynamics of theEarth’s atmosphere and ocean, but also the fluid dynamics of such things as the Earth’sinterior, volcanoes, lava flows and planetary atmospheres; it is the fluid mechanics of all things geophysical. But at the same time the appellation ‘GFD’ implies a certain austerity, and the subject is often seen as the one that provides the fundamental principles and languagfor understanding geophysical flows without being suffocated by the overwhelming detail of the real world. In this book we are guided by the ascetic spirit of GFD, and my hope isthat the reader will gain a solid grounding in the fundamentals, motivated by and with anappreciation for the problems of the real world.The book is an outgrowth of various courses that I have taught over the years, mainly atPrinceton University but also at the University of California and at summer schools or similarin Boulder and Kyoto. There are four parts to the book: fundamentals of geophysical fluiddynamics; instabilities, wave-mean flow interaction and turbulence; atmospheric circulation;and ocean circulation. Each corresponds, very roughly, to a one-term graduate course,although parts could also be used for undergraduates. Limitations enforced both by theneed to keep the book coherent and focused, and my own expertise or (especially) lack thereof, naturally limit the choice of topics. In particular the chapters on the circulationfocus on the steady and statistically steady large-scale circulation and perforce a number of important topics are omitted — tropical and equatorial dynamics, many of the effects of moisture on atmospheric circulation, the spin-up of the ocean circulation, atmospheric and oceanic tides, the quasi-biermial oscillation, and so on. I have however — and at no extra charge, mind you — discussed the large-scale circulation of both atmosphere and ocean. The similarities and differences between the two systems are, I believe, so instructive thateven if one’s interest is solely in one, there is much to be gained by studying the other. Thereferences at the end of the book are representative and not exhaustive, and almost certainlydisproportionately represent articles written in English and those with which I happen to be familiar. For the benefit of the reader interested in exploring the development of the subject I have included references to a number of historical articles, even when the presentation given does not draw from them. If there are other references that are particularly relevant I trust the reader will inform me. I have tried to keep the overall treatment of topics as straightforward and as clear as I know how. In particular, I have tried to be as explicit as possible in my explanations, even at the risk of descending from pedagogy into pedantry. Relatedly, there is a certain amount of repetition between sections, and this serves both to emphasize the important things and to keep chapters reasonably self-contained. The chapters are of course intellectually linked, for example, heat transport in the atmosphere depends on baroclinic instability, but hopefully the reader already familiar with the latter will be able to read about the former without too much cross-referencing. The treatment generally is fairly physical and phenomenological, and rigour in the mathematical sense is absent; I treat the derivatives of integrals and of infinitesimal quantities rather informally, for example.The figures (many in colour) may all be downloaded from the CUP w'eb site associated with this book. An asterisk, *, next to a section heading means that the section may be omitted on first reading; although normally uncontroversial, it may contain advanced material that is not essential for subsequent sections. A dagger, f. next to a section heading means that the section discusses topics of research. Very roughly speaking, one might interpret as asterisk as indicating there is advanced manipulation of the equations, whereas a dagger might indicate there is approximation of the equations, or an interpretation that is not universally regarded as settled; caveat emptor. There is some arbitrariness in such markings, especially w'here the section deals with a well understood model of a poorly understood.