Every profession has its savants - geniuses who appear on the scene once in a generation to turn the accepted wisdom on its head. Psycho analysts had Sigmund Freud; economists had John Maynard Keynes; architects had Le Corbusier and Frank Lloyd Wright; and meteorologists remember Vilhelm Bjerknes who died 50 years ago today, on April 9th, 1951.
Bjerknes was born in 1862, and spent much of his adult life as a university professor in Leipzig. In 1917, he returned to his native Norway to establish "an improvised weather service" to meet the needs of the fishing fleet of this small maritime nation. In Bergen, in a little office overlooking the harbour, he established a small team of extraordinary talent.
Within five years, "the Bergen school", as it came to be called, had made perhaps the greatest discoveries in meteorology. The concept of the moving depression had been familiar for over a century; the progress of these areas of low pressure could be followed on successive weather maps, and it was known that rain was associated with certain sectors of the depression, but the pattern appeared disorganised.
The great achievement of Bjerknes and his team was to reveal with brilliant clarity the detailed structure of a mid-latitude depression. Drawing on the military terminology familiar after the recent war, they introduced the concepts of warm and cold fronts, separating air masses with differing characteristics of temperature and humidity.
Like many new ideas, the concept of fronts took some time to be universally accepted. As the English meteorologist R.C. Sutcliffe said shortly after Bjerknes's death: "The clear lines of the bold and elegant Norwegian draughts man ship appealed immediately to scientists who saw, or thought they saw, the hallmark of truth in the very simplicity of the generalisations; but meanwhile, the professional meteorologist, the man who sought to use the new tools in his daily never-ending duties, was often sceptical and often disillusioned." But by the late 1930s, air mass and frontal analysis had been adopted by all the major weather services of the world, and survives today as the foundation stone of weather forecasting.
Shortly before his death, Bjerknes, never bashful about the achievements of the Bergen school, summed up its significance: "For 50 years meteorologists all over the world looked at weather maps without discovering their most important feature. I only gave the right kind of maps to the right young men, and very soon they discovered the wrinkles in the face of the weather."