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Figure 1. Walter (left) with Harald Sverdrup, Director of Scripps, in the George H. Scripps Memorial Marine Biological Laboratory building at Scripps Institution of Oceanography (circa 1940). Harald was working on his epic The Oceans. Photo from Scripps Institution of Oceanography Archives.
Scripps was then a small institution with a staff of about 15 led by Harald Sverdrup, the distinguished Norwegian Arctic explorer. Following the summer job, Walter returned to Cal Tech for a Master’s Degree, and then the next summer, back at Scripps, he convinced Sverdrup to take him on as a PhD student (Figure 1).
According to Walter, for a time he constituted Scripps’ entire student body. He applied for US citizenship when Nazi Ger- many invaded Austria. Anticipating the outbreak of war, he interrupted his studies, enlisted in the US Army, and spent the next year and a half in the Field Artillery and, because he was an avid and expert skier, in the Ski Troops. One gathers from stories he tells of those eighteen months that neither he nor the army were unhappy when he was excused from mili- tary service in order to pursue defense research at the Uni- versity of California Division of War Research (UCDWR) with offices at the US Navy Radio and Sound Laboratory in San Diego. Walter says that he was so ineffective as a private that he was promoted to corporal, and he was so good at that that he was promoted back to private.
For the next six years, Walter and colleagues from Scripps at the UCDWR worked primarily on issues related to amphibi- ous landings, starting with developing a forecast system for wave conditions to be expected during the planned Allied landing on the northwest coast of Africa. In winter the coast is subject to a northwesterly swell that produces breakers ex-
ceeding six feet on two out of three days. Because the LCVP (Landing Craft, Vehicle, Personnel) tended to broach in seas exceeding six feet, the problem of predicting the right day for the landing was critical to its success. Based almost en- tirely on empirical data, Sverdrup and Munk developed an analytic representation for a storm-generated, sea-surface spectrum based on wind speed and fetch and then calculated how it would be attenuated beyond the area of the storm and how it would be transformed in shallow areas. The ultimate prediction for the Normandy invasion based on their work was correct—the seas would be rough but would permit landings. This work was published in the now classic H.O. 601 (Sverdrup and Munk, 1947), and the method was used to predict sea conditions for amphibious landings in both the Pacific and Atlantic theaters. A prescient aspect of this work (aside from the fact that it yielded very good predic- tions!) was that it produced what amounted to a sea-surface spectrum years before an analytic spectral description of sea state was introduced.
In many ways this early work illustrates Walter’s modus ope- randi. Pick a difficult problem with a big payoff, develop physical insight before equations, rely on data and observa- tion, collaborate with colleagues, both scientists and engi- neers, knit it all together with great mathematical facility, and explain it simply and clearly. When working with col- leagues, he always shoulders far more than his share, and even though he does more of the work than anybody, he takes less of the credit. He is particularly insistent that young people, especially students, be recognized for their contribu- tions.
Walter has a self-professed, unique, personal philosophy. He says he chooses not to spend time polishing lectures because students learn more if they participate in halting derivations and have the joy of pointing out blunders. Yet anyone who has heard Walter’s clear, concise, organized, and often hu- morous talks, speeches, and lectures might justly wonder about the truth of this assertion. His colleague Christopher Garrett has accused him of not letting the truth get in the way of a good seminar.
Walter has said, “I do not like to read.” It may be true, but he obviously reads voraciously. One of the great joys of his writing is the wonderful way he puts things into historical perspective with his virtually photographic memory of facts and figures that can go back to Devonian times when the year had 400 days! We think Walter’s philosophy is like his sense of humor—mischievous, with tongue in cheek.
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