A Planetary-Scale to Mesoscale Perspective of the Life Cycles of Extratropical Cyclones: The Bridge between Theory and Observations

Abstract

The emergence of meteorology as a rational science began around the turn of the twentieth century when Max Margules, Hermann Helmholtz, Felix Exner, and Vilhehn Bjerknes formulated the theoretical basis for what was previously considered an empirical science with a qualitative application to weather forecasting and climatology. The concurrent synoptic studies of Sir Napier Shaw, Rudolph Lempfert, Johan Sandstrom, V. Bjerknes, and Heinrich von Ficker, among others, provided insight into the structure and evolution of weather systems, and an assessment of the represen-tativeness of the proposed theories. The synergy between dynamic and synoptic meteorology inspired new theories, observing strategies, conceptual models, and dramatic advances in weather forecasting. During the period 1913–1922, the Leipzig and Norwegian schools of meteorology made fundamental contributions to the advancement of the emerging science. With V. Bjerknes as their director and mentor, the research associates and students at the Geophysical Institutes in Leipzig, Germany, and Bergen, Norway, synthesized theory, observations, synoptic analysis and diagnosis in their quest for physical understanding and improved weather prediction. Their efforts gave rise to revolutionary paradigms for the theory, structure, and evolution of frontal cyclones, many of which remain widely applied in research and weather forecasting. A historical perspective of the science and the milieu of the period is reviewed in the works of Bergeron (1959), Kutzbach (1979), Friedman (1989), and in the historical chapters in this volume by Eliassen (1998), Friedman (1998), Newton and Newton (1998), and Volkert (1998).