Vilhelm Bjerknes
Bjerknes, Vilhelm (1862-1951), was a Norwegian physicist whose work in hydrodynamics helped to lay the foundations for the science of modern meteorology.
The son of a mathematics professor, Vilhelm Friman Koren Bjerknes became interested in his father's research in hydrodynamics, the branch of physics that deals with the forces that water and other liquids in motion exert. He received a doctorate in physics in 1892 from the University of Christiania (renamed the University of Oslo in 1925). In 1895, Bjerknes became professor of applied mechanics and mathematical physics at the University of Stockholm.
Using theorems concerning the velocities of circulation and taking into account the sun's heat and the friction of atmospheric motion, Bjerknes studied the atmosphere and the ocean, nature's largest fluid systems. From 1905 to 1941, the Carnegie Foundation supported his work in physical weather prediction. In 1907, Bjerknes left Stockholm to become a professor at the University of Christiania. In 1912, he accepted a professorship of geophysics at the University of Leipzig. He returned to Norway again in 1917, where he founded the Bergen Geophysical Institute.
During World War I (1914-1918), Bjerknes established a series of weather station throughout Norway. Information from these stations led him and his colleagues at the Bergen Geophysical Institute, to the theory of polar fronts, based on the discovery that distinct air masses with different features make up the atmosphere. Bjerknes borrowed the word “front” from military terminology, where it describes the place where warring armies carry on combat operations. In the meteorological sense, a front is the between dissimilar air masses. Among other things, the frontal theory explained how cyclones form from atmospheric fronts where cold and warm air masses meet over the Atllantic Ocean.
In 1921, Bjerknes's work On the Dynamics of the Circular Vortex, with Applications to the Atmosphere and to Atmospheric Vortex and Wave Motion, was published. It explained the essential aspects of his research and became a classic.