The Science of Ocean Waves: Ripples, Tsunamis, and Stormy Seas, J. B. Zirker, Johns Hopkins U. Press, 2013. $39.95 (248 pp.). ISBN 978-1-4214-1078-4
Few topics in physics can match the complexity of air–sea interactions. So it is no wonder that an astrophysicist, a practitioner in a similarly complex system, took up the challenge of summarizing for the general reader the modern scientific view on ocean waves.
In his new book, The Science of Ocean Waves: Ripples, Tsunamis, and Stormy Seas, J. B. Zirker offers a comprehensive and up-to-date account of a familiar phenomenon whose complexity is hardly appreciated by nonscientists. Zirker’s deep insights, historic perspectives, and excellent narrative, which he provides with minimal graphics and without a single equation, make the book a fascinating read. It is also an unusual approach to a topic that has commanded the attention of mathematicians, physicists, oceanographers, meteorologists, and engineers for almost 200 years, and especially in the past 60 years.
Wind-generated waves, even in their relatively simple deep-water incarnation, illustrate the complexity of ocean waves. They are produced by turbulent air, dissipated through violent and sporadic breaking, and evolve due to weak and slow nonlinear interactions between waves of different scales. All those processes are equally important and therefore need to be modeled and solved simultaneously. But they play out over time scales that range from a fraction of a wave period to thousands of wave periods. And our understanding of those processes ranges from pretty good to zero. In addition to those intricacies, we should consider waves in finite depths and add the effects of extreme weather. Moreover, waves come in a wide range of sizes—from tiny capillary waves to enormous planetary-scale waves—and propagate in many distinct environments governed by their own specific physics.
After a brief introduction into the general concept of waves as propagating oscillations—in particular, waves on the ocean surface—the first half of the book is dedicated to theoretical and experimental research on wind-generated waves. The author rigorously presents the fundamental insights developed in the 20th century on water and ocean waves—for example, the Zakharov equation, the Hasselmann integral, the Benjamin–Feir instability, and the Jeffreys, Phillips, and Miles theories for wave generation. The presentation is suitable for a professional scientist and for a person with a basic background in physics and oceanography.
Essential to ocean-wave research are experimental studies, which are numerous in the field. The author consistently highlights significant experimental milestones, including the measurements that led to the benchmark 1964 parameterization by Willard Pierson and Lionel Moskowitz of a “fully developed sea,” the Joint North Sea Wave Project observations in 1973 that modified the Pierson–Moskowitz result, and the modern-day satellite remote sensing of ocean waves. He also makes a good attempt to describe rogue waves and the dynamics of wave breaking—the field’s most elusive aspects—which are difficult to probe experimentally and still lack consistent theoretical approaches. The topic of numerical wave modeling is reviewed in detail. Zirker’s may be the first book to reconstruct the continuing development of that important approach from the early attempts dictated by naval needs during World War II to modern-day global-wave forecasts and hindcasts.
The book’s second half is dedicated to large-scale waves and engineering applications related to ocean waves. Zirker describes tsunamis; internal waves, including such subtle phenomena as Kelvin and Rossby waves; storm surges; tides; and even ocean currents. He outlines how some of them can be connected to the climate system through El Niño events. The last two chapters sketch maritime engineering problems such as ship waves, which slow ships down, and how those problems are linked to naval architecture and the increasingly relevant issue of harnessing ocean-wave energy.
The final chapter, “The Future,” depicts the author’s expectations for developments in ocean-wave science. Quite rightly, he stresses the role— yet to be fully appreciated—of ocean waves in large-scale air–sea interactions and climate systems. He also properly emphasizes improved high-spatial-resolution satellite observations of the ocean and ultrafast and powerful supercomputing as supports and complements to experimental efforts. His several predictions include a new generation of ocean and wave forecast models and better understanding of complex nearshore dynamics and the coupling of microscale-wave-related processes with various air–sea exchanges.
The Science of Ocean Waves is a truly remarkable achievement. It has a great chance to become a standard text for students, scientists, weather and ocean forecasters, engineers, climate modelers, and anyone else whose curiosity or professional interests relate to ocean waves.
Alexander Babanin is a founding director of the Centre for Ocean Engineering, Science, and Technology at Swinburne University of Technology in Melbourne, Australia. For more than 30 years, he has researched ocean waves, wave-coupled effects in the lower atmosphere and upper ocean, remote sensing of the ocean, and ocean and coastal engineering applications.
