1. IFAECI, CNRS/CONICET/UBA, Buenos Aires, Argentina
2. Computer Science Department, University of California, Los Angeles, Los Angeles, California
3. Environmental Change Institute, University of Oxford, Oxford, United Kingdom
4. LSCE, CNRS/CEA, Gif-sur-Yvette, France
5. École Normale Supérieure, Paris, France, and Department of Atmospheric and Oceanic Sciences, University of California, Los Angeles, Los Angeles, California