The cause was pneumonia, said his wife, Mary Munk.
Long associated with the Scripps Institution of Oceanography at the University of California at San Diego, Dr. Munk was one of the most celebrated oceanographers of his era — a scientist who devoted nearly eight decades to unraveling such questions as where waves begin, why they may break violently or wash ashore gently, how sound travels thousands of miles through water, and what information that journey might reveal about the global ecosystem.
His “genius lay in divining the interlocked patterns beneath the seeming clutter and chaos of the world’s oceans,” Josh Horwitz, who profiled Dr. Munk in his book “War of the Whales,” wrote in an email. “He was revered in equal measure by surfers and navy admirals for his oracular ability to predict when far-off waves would break on beaches.”
Much like the surfers of popular imagination, Dr. Munk found a home on the beaches of California, where he had fled to avoid a life on Wall Street. Born in Vienna to an affluent banking family, he had come to the United States in the early 1930s to attend a boarding school in New York and to carry on the family profession. But he soon discovered that he despised banking, bought a convertible and set out for the West Coast.
He abandoned finance for science, eventually landing at Scripps, where he apprenticed himself to the director, Harald Sverdrup, a leading oceanographer of his day.
In 1938, Nazi Germany annexed Austria and accelerated a campaign of anti-Semitic persecution. Dr. Munk, whose family had Jewish roots, became a U.S. citizen and served briefly in the Army before beginning what would be his seminal research for the Navy.
Dr. Munk credited Sverdrup with playing a leading role in the development of wave forecasting, which military strategists used in the planning of the amphibious landing on North Africa in 1942, in the Normandy invasion in 1944 and throughout the Pacific.
The publication New Scientist credited Dr. Munk with saving “countless lives by helping the Allied military determine when troops could make amphibious landings without being swamped by big surf hundreds of meters from a hostile shore.”
Later in his career, he attracted wide attention, as well as some controversy, by using ocean acoustics to measure ocean temperatures, and thus to better understand climate change.
“Munk had an idea,” Enric Sala, a marine ecologist and National Geographic Society explorer-in-residence, wrote in an email, describing an experiment that Dr. Munk led near Heard Island, in the southern Indian Ocean, in 1991. Understanding that sound travels more quickly in warm water than it does in cold water, Dr. Munk sent low-frequency sounds through the ocean. Even the test signal was detected in Bermuda.
“I still can’t believe that happened,” Dr. Munk told the San Diego Union-Tribune years later. “We hadn’t even started the main experiment.”
Through the experiment, Sala said, Dr. Munk “was able to prove at such large scales for the first time that different oceans were warming at different speeds.” Such acoustic tests encountered some opposition from marine biologists who feared that they might interfere with migratory patterns of whales and other animals.
For the wide-ranging nature and applications of his work, Dr. Munk was dubbed the “Einstein of the oceans,” a comparison that Dr. Munk rejected. “Einstein was a great man,” he once told the Union-Tribune. “I was never on that level.”
Walter Heinrich Munk was born on Oct. 19, 1917. His father served for a period as chauffeur to Emperor Franz Joseph of Austria. Years later, in an interview with the New York Times, Dr. Munk recalled that his father had “the only Rolls-Royce in Vienna.” He often recalled the DeSoto convertible that he drove from New York to his new life in California.
He attended the California Institute of Technology, where he received a bachelor’s degree in physics in 1939 and a master’s degree in geophysics in 1940, and the University of California at Los Angeles, where he received a PhD in oceanography in 1947.
After the war, Dr. Munk provided scientific support for the nuclear testing at Bikini Atoll. “It’s stunning; it’s horrible,” he told the Associated Press years later. “It’s not dark, it’s quite white. You see the boiling and the water vapor above you, like a curtain coming down all around you.”
Throughout the Cold War and beyond, he served with the Jasons, a group of scientists advising the U.S. military.
His first marriage, to Martha Chapin Munk, ended in divorce, and his second wife, the former Judith Horton, died in 2006 after more than 50 years of marriage. Survivors include his wife of seven years, the former Mary Coakley of La Jolla; two daughters from his second marriage, Kendall Munk of State College, Pa., and Edie Munk of La Jolla; and three grandsons. Another daughter from his second marriage, Lucian, died at 7 of a heart ailment.
Dr. Munk’s honors included the National Medal of Science, bestowed on him by President Ronald Reagan in 1983, and a 1999 Kyoto Prize in basic sciences. Horwitz recalled that when Dr. Munk accepted the 2010 Crafoord Prize in Geosciences from the Royal Swedish Academy of Sciences — an award often compared to the Nobel, recognizing a career that touched on waves and polar ice caps and warming seas — he opened a lecture about climate change by citing from Samuel Taylor Coleridge’s classic poem “Kubla Khan”:
The shadow of the dome of pleasure
Floated midway on the waves;
Where was heard the mingled measure
From the fountain and the caves.
It was a miracle of rare device,
A sunny pleasure-dome with caves of ice!
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