The Weather and Climate: Emergent Laws and Multifractal Cascades

Shaun Lovejoy is Professor of Physics at McGill University, Montréal, and has been a pioneer in developing and applying new ideas in nonlinear dynamics to the geosciences since the late 1970s. This has included multifractals, generalized (anisotropic) scale invariance, universal multifractals, space-time multifractal modeling of geofields (especially clouds, precipitation and topography). He has published over 200 papers applying these ideas to the Earth and environmental sciences. The unifying theme of this work is that when the notion of scaling is generalized to include anisotropy and multifractality, many key geofields display scaling behaviour over enormous ranges of scale; and that this nonclassical extreme variability is a new paradigm for the geosciences. In addition to these scientific contributions, Professor Lovejoy has actively promoted nonlinear processes in geophysics by co-founding the Nonlinear Process section at the European Geosciences Union (EGU) and the Nonlinear Processes in Geophysics journal. He has been Vice-chair and subsequently Chair of the Nonlinear Geophysics focus group at the American Geophysical Union (AGU) since 2004. Daniel Schertzer is a professor at École des Ponts ParisTech, Université de Paris-Est, and Scientific Director of the Chair 'Hydrology for Resilient Cities', sponsored by VEOLIA Water. His research introduced multifractals and related techniques in hydrology, after having contributed to their theoretical developments in turbulence, in particular with the definition of a co-dimension formalism, the concepts of generalized scale invariance and universal multifractals. His work has covered many domains of geophysics and the environment, with a particular emphasis on atmospheric dynamics, precipitation extremes and remote sensing. His publications include two books and 115 ISI-indexed publications, which have received more than 4000 citations, and he is executive editor of the journal Nonlinear Processes in Geophysics, which he co-founded as well as the nonlinear geophysics divisions of European Geophysical Union (EGU) and American Geophysical Union (AGU). Professor Schertzer has been a union officer of the EGU and an officer of AGU committees and the International Association for Hydrological Sciences bureau. He is also vice-president of the French National Committee of Geodesy and Geophysics, and a member of the Higher Council of Meteorology (France).