(Deborah Day, Scripps Institution of Oceanography Archives,21 August 2002)
Harald Ulrik Sverdrup was a Norwegian oceanographer and meteorologist who studied and worked in Bergen and Leipzig and then became the scientific director of the North Polar expedition of Roald Amundsen aboard the Maud from 1918 to 1925. His measurements of bottom depths, tidal currents, and tidal elevations on the vast shelf areas off the East Siberian Sea correctly described the propagation of tides as Poincare waves. Upon his return to Norway, he became the chair in meteorology at the University of Bergen.
In 1936, he was named director of California's Scripps Institution of Oceanography and held the post until 1948. During 33 expeditions with the research vessel E. W. Scripps in the years 1938-1941 he produced a detailed oceanographic dataset of the coast off California. He also developed a simple theory of general ocean circulation, postulating a dynamical vorticity balance between the wind-stress curl and the meridional gradient of the Coriolis parameter--Sverdrup balance. This balance describes wind-driven ocean gyres away from continental margins at western boundaries. After leaving Scripps, he returned home to become director of the Norwegian Polar Institute and continued to contribute to oceanography, ocean biology and polar research. In biological oceanography, his Critical Depth Hypothesis, published in 1953, was a significant milestone in the explanation of phytoplankton spring blooms.
His many publications include The Oceans: Their Physics, Chemistry and General Biology (1942), which formed the basic curriculum of oceanography for the next 40 years worldwide.
The sverdrup (Sv) is used in physical oceanography as an abbreviation for a volume flux of one million cubic meters per second.