1 Introduction

The subject of geophysical fluid dynamics deals with the dynamics of the atmosphere and the ocean. It has recently become an important branch of fluid dynamics due to our increasing interest in the environment. The field has been largely developed by meteorologists and oceanographers, but non-specialists have also been interested in the subject. Taylor was not a geophysical fluid dynamicist, but he held the position of a meteorologist for some time, and through this involvement he developed a special interest in the problems of turbulence and instability. Although Prandtl was mainly interested in the engineering aspects of fluid mechanics, his well-known textbook (Prandtl, 1952) contains several sections dealing with meteorological aspects of fluid mechanics. Notwithstanding the pressure for specialization that we all experience these days, it is worthwhile to learn something of this fascinating field even if one's primary interest is in another area of fluid mechanics.

The importance of the study of atmospheric dynamics can hardly be overem-phasized. We live within the atmosphere and are almost helplessly affected by the weather and its rather chaotic behavior. The motion of the atmosphere is intimately connected with that of the ocean, with which it exchanges fluxes of momentum, heat and moisture, and this makes the dynamics of the ocean as important as that of the atmosphere. The study of ocean currents is also important in its own right because of its relevance to navigation, fisheries, and pollution disposal.

The two features that distinguish geophysical fluid dynamics from other areas...