Born in Christiania, Bjerknes enjoyed an early exposure to fluid dynamics, as his father Carl Anton Bjerknes, in his mathematical research. In 1890, he became assistant to Heinrich Hertz and made substantial contributions to Hertz' work on electromagnetic resonance. In 1895, he became professor of applied mechanics and mathematical physics at the University of Stockholm where he elucidated the fundamental interaction between fluid dynamics and thermodynamics. His major contribution was the primitive equations which are used in climate models[1] . It was this work that inspired both V. Walfrid Ekman and Carl-Gustav Arvid Rossby to apply it to large-scale motions in the oceans and atmosphere and to make modern weather forecasting feasible. Bjerknes himself had foreseen the possible applications as early as 1904. In 1907, Bjerknes returned to the The Royal Frederick University in Oslo before becoming professor of geophysics at the University of Leipzig in 1912. In 1917, he founded the Bergen Geophysical Institute where he wrote his book On the Dynamics of the Circular Vortex with Applications to the Atmosphere and to Atmospheric Vortex and Wave Motion (1921) and laid the foundation for the "Bergen School of Meteorology". From 1926 to his retirement in 1932 he held a position at the University of Oslo, where he died of heart problems. He was elected a member of the Royal Swedish Academy of Sciences in 1905. His son was the meteorologist Jacob Bjerknes (1897-1975). The crater Bjerknes on the Moon and a crater on Mars are named in his honor.