Harald Ulrik Sverdrup (November 1888-August 1957) was a Norwegian oceanographer and meteorologist who made a number of important theoretical discoveries in these fields. Having first worked in Bergen and Leipzig he was involved in the North Polar expedition of Roald Amundsen between 1917 and 1925, before taking the chair in meteorology at Bergen, where his primary interest slowly became oceanography.
He was made director of California's Scripps Institute of Oceanography (SIO) in 1936, initially for 3 years but the intervention of World War II meant he held the post until 1948. While there he developed the theory of ocean circulation known as Sverdrup balance, the first truly accurate description of the phenomenon. After leaving SIO, he returned home to become director of the Norwegian Polar Institute and continued to contribute to oceanography, ocean biology and polar research.
He was a member of the US and Norwegian Academies of Science and the Swedish Order of the North Star. A unit of volume flux bears his name.