John Crossley Swallow
John Swallow was best known for his invention of the neutrally buoyant float (otherwise known as the “Swallow Float”) and its pioneering use in uncovering important elements of the ocean's general circulation. The first of these was the Deep Western Boundary Current on the Continental Rise south of Cape Cod, a joint discovery with Val Worthington, and a crucial part of the ocean's thermal engine.
At the time they were pursuing a prediction from Henry Stommel's theoretical model for deep circulation. It suggested that the water carried equatorward in the deep western boundary currents must be brought back to the poles by slowly bleeding into the interior, and then drifting sluggishly poleward and upward through the main thermocline. Swallow, with assistance from Stommel, set out with his floats to confirm this slow, poleward drift in the ocean interior using a 100-foot ketch named Aries. Expecting to be able to return periodically to obtain new fixes ion his floats, Swallow was soon surprised to find that the floats moved much more quickly: He had come upon the mid-ocean mesoscale eddy field that subsequently launched a whole decade of research in such large international programs as the Mid-Ocean Dynamics Experiment (MODE) and its follow-on POLYMODE, and radically changed our perception of the ocean.
The scientific collaboration between Swallow and Stommel continued, first in the MEDOC experiment, an investigation into wintertime convective processes in the northwest Mediterranean Sea, and then in the International Indian Ocean Expedition. Swallow’s interest in the Indian Ocean continues to this day. Retirement from the UK Institute of Oceanographic Sciences, Deacon Laboratory, Wormley, in 1983 seems only to have quickened the pace of cruises and publications. His capacity for hard work at sea is legendary as is his careful and thoughtful analysis of the data collected.
Swallow began his professional life not as a physical oceanographer, but as a geophysicist, and was awarded a Ph.D. at Cambridge University for a thesis entitled “Seismic Investigations at Sea.” He began work at what was then called National Institute of Oceanography in 1954 and developed the neutrally buoyant float that became the basis for much of his subsequent exploration of the ocean. In 1962 he was awarded WHOI’s Henry Bryant Bigelow Medal, principally for the invention of the Swallow float and co-discovery of the Deep Western Boundary Current. He was made a Fellow of the Royal Society in 1965 and a Foreign Honary Member of the American Academy of Sciences of Arts and Sciences in 1975. He has also received the Sverdrup Medal from the American Meteorological Society (1978) and the Prince Albert I of Monoco Medal (1982) among other honors. He and Henry Stommel were long-time friends, and Henry would be especially pleased to know that the first recipient of the medal cast in his honor was John Swallow.
Nelson G. Hogg, Chair
William B. Curry
Holger W. Jannasch
Frederick L. Sayles
Timothy K. Stanton
Originally published: February 15, 1994