meteorologist who specialized in both dynamic meteorology, concerned with atmospheric motions and the forces creating them, and synoptic meteorology, which uses charts and weather observations for the identification, study, and forecasting of weather.

Petterssen was a meteorologist with the Norwegian Meteorological Service (1924–31), advancing to regional director (1931–39). He went to the Massachusetts Institute of Technology, Cambridge, in 1939, becoming professor and chairman of the meteorology department (1940–42) and writing Weather Analysis and Forecasting (1940) and Introduction to Meteorology (1941). He served with the British Air Ministry during World War II and then returned to the Norwegian Meteorological Institute, Oslo. Back in the United States, he joined the weather service of the Air Force (1948–52) and became professor of meteorology at the University of Chicago (1952–63), chairman of meteorology (1959–61), and chairman of geophysical science (1961–63). He was co-author, with W.C. Jacobs and B.C. Haynes, of Meteorology of the Arctic (1956).