The El Niño-Southern Oscillation Phenomenon


Sarachik, E.S., Cane, M.A. 2010. The El Niño-Southern Oscillation Phenomenon. Cambridge, United Kingdom: Cambridge University Press.


This is a book about the set of coupled atmosphere-ocean phenomena known collectively as ENSO (El Niño-Southern Oscillation). While it will concentrate on what is known about ENSO, its mechanism, its effects, and how predictable it is, it will also touch on what is known about the paleohistory of ENSO and what we might expect in the future as mankind puts CO2 and other radiatively active constituents into the atmosphere. The approach, while theoretical and sometimes necessarily mathematical, will concentrate on observations and on physical principles.

Because ENSO is an intrinsically coupled ocean-atmosphere process, we will introduce the essentials of both the tropical atmosphere and ocean and explain the unique properties of each medium. Because ENSO is an intrinsically Pacific phenomenon, we will explain the unique aspects of the tropical Pacific and which of its features makes it particularly congenial for the existence of ENSO. We will describe those tropical atmospheric and oceanic mechanisms that ultimately help to explain the mechanism of ENSO. While there is not general agreement about what the ENSO mechanism is, we would expect that a similar book written a decade or so henceforth would contain much of the same material. In pursuit of the ENSO mechanism throughout this book, these themes will recur: the ability of warm sea surface temperature to anchor regions of persistent precipitation; the ability of regions of persistent precipitation to induce surface westerly wind anomalies to the west of these regions; the tendency of anomalously warm sea surface temperature anomalies in the Pacific to become warmer by local processes; and the tendency of cold sea surface temperature anomalies to be associated with shallower thermoclines.

Each chapter will begin with a short précis which will indicate the broad outlines of the chapter. The book will conclude with a recap which will mirror, but not repeat, the content of the book. It is hoped that in this way, the reader will be able to read the book in a manner suitable for his or her ability and needs. Essential mathematics will be relegated to the appendices. Some exercises will be interspersed in the chapters in order to give the reader the useful practice of deriving some basic results.

The aim of the authors is to produce a book that can be read on many levels by many audiences, depending on their interests and capabilities. Anyone reading the Preview, the chapter headings, and the final Postview chapter will get a very complete idea of what this book is about. We view our audience as scientists who are at least familiar with the nature of scientific explanation while perhaps not being familiar with the nitty-gritty of fluid mechanics, meteorology, or oceanography. We expect that a second year graduate student in meteorology or oceanography would have enough basic background to work through the entire book.