Carl-Gustaf Rossby

Carl-Gustaf Rossby was a Swedish-born American meteorologist who was among the first scientists to explain large-scale atmospheric motion in terms of fluid mechanics. While at the University of Chicago, which he joined as department chair in 1940, Rossby identified and characterized the jet stream, the narrow band of fast-moving air high in the atmosphere that strongly influences weather patterns in the mid-latitudes. Rossby identified long wave patterns in the upper-level westerly winds that came to be named Rossby waves in his honor, and after the Second World War his collaboration with German meteorologist Hans Ertel led to a rigorous mathematical formulation describing these waves. Rossby became a naturalized United States citizen in 1939, served as an associate professor at MIT beginning in 1928, and later became founding director of the Swedish Meteorological and Hydrological Institute in 1947; he received the Symons Gold Medal in 1953 and in December 1956 became the first meteorologist ever to appear on the cover of Time magazine.