Wave breaking is a fascinating object to watch and to research. Wind-generated waves are the most prominent feature of the ocean surface, and so are breaking waves manifested by sporadic whitecaps on the wavy surfaces of oceans and lakes. The breaking is so apparent that one does not need to be an oceanographer to have an opinion on what it is and how it works.

Such breaking, however, represents one of the most interesting and most challenging problems for both fluid mechanics and physical oceanography. It is an intermittent random process, very fast by comparison with other processes in the wave system. The distribution of wave breaking on the water surface is not continuous, but its role in maintaining the energy balance within the continuous wind–wave field is critical. Ocean wave breaking also plays the primary role in the air–sea exchange of momentum, mass and heat, and it is of significant importance for practical applications such as ocean remote sensing, coastal and ocean engineering, and navigation among others.

Understanding such wave breaking, predicting its behaviour, the breaking rates and breaking strength, and even an ability to describe its onset have been hindered for decades by the strong nonlinearity of the process, together with its irregular and ferocious nature. Lately, knowledge of the breaking process has significantly advanced, and this book is an attempt to summarise the facts into a consistent, albeit still incomplete, picture of the phenomenon.