He did the his PhD in atomic physics at the Danish Technical University and a Doctor of Science in Turbulence and Climatology. He was a post doctoral researcher at the University of California in Berkeley, researcher at the Danish Meteorological Institute, guest researcher at the National Center for Atmospheric Research in Boulder, Colorado and the Carlsberg Foundation researcher at the Niels Bohr Institute before he had a permanent position. His area of research is in statistical physics, the physics of complex systems, chaos, turbulence and the physics of the atmosphere and the climate. He is involved in the the Greenland ice-coring project. He has published more than 50 papers and authored 2 books. He is esteemed teacher at the Niels Bohr Institute.