Vilhelm Bjerknes

Vilhelm Bjerknes was a Norwegian meteorologist and physicist who made significant contributions to the fields of fluid dynamics, electromagnetism, and weather forecasting. He was the son of a mathematician and physicist, Carl Anton Bjerknes, who discovered the analogy between electric and hydrodynamic phenomena. Vilhelm assisted his father with his research and experiments, and also studied under Heinrich Hertz in Germany. He discovered the circulation theorems that relate the flow of fluids to the forces acting on them, and applied them to the atmosphere and the ocean. He also developed the primitive equations that describe the large-scale motions of the atmosphere, and are still used in numerical weather prediction and climate modeling. He proposed a program for physical weather prediction, based on the idea of describing the state of the atmosphere by variables such as pressure, temperature, and humidity, and using mathematical equations to calculate their changes over time. He founded the Bergen School of Meteorology, which was influential in advancing the science of weather forecasting in the early 20th century. He also introduced the concept of air masses and fronts, which are the main features of weather systems. He received many honors and awards for his work, including the Buys Ballot Medal, the Symons Gold Medal, and the Gunnerus Medal. He was elected a foreign member of the Royal Society and several other academies. He died of heart failure in Oslo at the age of 89.