1. Department of Earth and Planetary Sciences, Weizmann Institute of Science, 76100 Rehovot, Israel
2. Max-Planck-Institut fur Meteorologie, D-20146 Hamburg, Germany
3. Department of Meteorology, Stockholm University, 10691 Stockholm, Sweden
4. Sorbonne Université, Laboratoire de Météorologie Dynamique (LMD)/Institut Pierre Simon Laplace (IPSL), Centre National de la Recherche Scientique (CNRS), Univ Paris 06, 75252 Paris, France