To chart ocean currents, oceanographers go with the flow
A View of the Sea, by Henry Stommel. Princeton, N.J.: Princeton University Press. 165 pp. $19.95. Visitors from another planet who see light as we do would have a vivid first impression of Earth when approaching from the black of outer space: a deep blue ball, laced with swirls of white and patches of brown. As they watch for hours, the white swirls dance, grow, and fade, but the blue remains fixed within its outlines. ``Why,'' they might ask, ``does the white move and not the blue?''
Our oceans do move, and their circulations largely determine the formation and evolution of clouds and climate. Henry Stommel, one of the world's experts on ocean circulation and a former professor at the Massachusetts Institute of Technology, sets out in this slim book to explain the factors that govern these massive movements of water. In the process, he shows how oceanographers arrive at this knowledge through measuring the properties of ocean waters and interpreting them with the physical laws of motion relating forces, accelerations, and velocities.
Throughout the book, Stommel develops an analogy between oceanic circulation patterns and the internal workings of a large machine. The literary device is an ongoing dialog between Stommel himself and Chief, a veteran chief engineer on the ocean research vessel, who wants to understand the oceans ``without having to cope with fancy words like `geophysical fluid dynamics.'... He has met smart alecks before.'' The concepts are essentially quantitative and are most concisely expressed in mathematical notation, which Stommel doesn't hesitate to use when appropriate.
We begin to see the character of a research scientist who revels in having been born in a century that allows him to earn a living at what he enjoys doing most. One passage illuminates this intensity: ``There is very little else to do but think and work. And the urge to express myself, to communicate my own view of the ocean - as limited and partial as it must be - is irrepressible. Of all the wonders of the universe, surely enjoyment of exercising our minds must be the greatest.''
There is much to be learned here about the scientific method, not in abstract definition but in continual use. As the observations on small ``blocks'' of ocean waters are collected and analyzed the data are examined for consistency with the physics of water flow. The resulting flow patterns from many blocks in different parts of the Atlantic are then assembled into a full-scale scientific model of ocean circulation. The predictions of the model are then compared with observations made on different ocean voyages over several decades. The model is put into mathematical form on a personal computer and refined until it explains measurements as accurately as possible. The results are then published for the entire community of oceanographers to read and scrutinize.
Stommel also shows that creative science is a social act. His colleagues - Ed Fredkin, the computer genius a quarter century ahead of his time; Jim Luyton, who ``had mathematical skills and insight far superior to my own''; and others - make seminal contributions to the model of ocean circulation Stommel develops and presents. Aspects of the theory often bear the names of their inventors, and through ``Rossby waves,'' ``Ekman pumps,'' and ``Sverdrup velocities'' we taste the international character of a scientific community.
The meat of ``A View of the Sea'' is not particularly tender. It will take time and patience to digest, because Stommel is describing his most current theory of ocean circulation, the subject of his own research papers published as recently as 1986. My guess is that his oceanographic colleagues will study it closely for hidden gems. The nonspecialist may find the intricacies of the arguments overwhelming at times, but often when the going gets toughest there is relief - a salty anecdote, a wry observation, a putdown from the Chief. As the book progresses, I find the Chief less believable as a character and more as a logical counterpoint to Stommel's arguments, but since the essence of ``A View of the Sea'' is scientific research, the transformation is not objectionable.
For the truly adventurous, computer-owning layman, an appendix presents ``nine little programs in Microsoft BASIC.'' The first illustrates a very simple motion of a particle rotating about the earth's axis and gravitating toward the earth's center, while the last is a 364-line research tool for the practicing oceanographer.
A five-week trip to the mid-Atlantic on a research vessel may not be for everyone. But those ready for the adventure of hearing a world-class scientist explaining both what he knows and how he came to know it will find ``A View from the Sea'' rewarding.
Allan Smith teaches chemistry at Drexel University.
