 In 1943, he was given the position of professor for meteorology and geophysics at the University of Innsbruck, and he also attended lectures by Arnold Sommerfeld.After Second World War, Ertel was interested in a professorship for geophysics at the University of Munich, but was instead appointed to professor for geophysics at Berlin University in 1946, where he also became the director of the Institute for Meteorology and Geophysics which belonged to the university.At the invitation of various scientists, such as Hilding Köhler, Markus Bath and Carl-Gustav Rossby, with whom he also maintained long friendships, Ertel held lectures at Stockholm University and Uppsala University in Sweden and took part in congresses, thereby creating a good reputation for his field of research at the Berlin University.