Born Mar. 23, 1839, in Linz; died Oct. 1, 1921, in Vienna. Austrian meteorologist.
From 1874 to 1897 and after 1900, Hann was a professor at the University of Vienna, and from 1877 to 1897 he was director of the Austrian Meteorological Institute. He was one of the founders of the Austrian Meteorological Society (1863) and the journal Meteorologische Zeitschrift. He formulated the so-called dynamic theory of cyclones, explaining that they are formed by the interaction of two opposing air currents. Hann studied the climates of the earth and described the foehn phenomenon.
WORKSHandbuch der Klimatologie, 4th ed. Stuttgart, 1932.
Lehrbuch der Meteorologie, vols. 1-2. Leipzig, 1939-51.
In Russian translation:
Obshchee zemlevedenie. St. Petersburg, 1902. (With E. Bruckner.)