Which scientist (1862-1951) pioneered the understanding of extra-tropical cyclones?

• A. Gaspard Gustave de Coriolis
• B. Charles Darwin
• C. Vilhelm Bjerknes
• D. Isaac Newton

Answer: (C)

Extra-tropical cyclones form where air masses with different temperatures meet in the mid-latitudes, and their development is driven by baroclinic processes along those fronts. Vilhelm Bjerknes, a Norwegian physicist and meteorologist who lived from 1862 to 1951, was the pioneer who showed how these storms arise and evolve. Working with students at the Bergen School, he and his collaborators developed the front-based picture of cyclone formation—the polar front between warm tropical air and cold polar air—and explained how a low-pressure center can intensify as the warm air rises and the cold air wraps around it. This work linked physical dynamics to observable weather patterns, laying the foundation for synoptic meteorology and early weather forecasting. The other figures contributed to different areas (for example, the Coriolis effect, Darwinian natural history, or classical mechanics) but did not pioneer the understanding of extra-tropical cyclones in the way Bjerknes did.