1. Institut f¨ur Umweltphysik, University of Heidelberg, INF 229, D-69120 Heidelberg, Germany;
2. Heidelberger Akademie der Wissenschaften, INF 229, D-69120 Heidelberg, Germany
3. Interdiszipliares Zentrum für wissenschaftliches Rechnen (IWR), University of Heidelberg, INF 368, D-69120 Heidelberg, Germany
4. Centre for Australian Weather and Climate Research / CSIRO Marine and Atmospheric Research (CMAR), Private Bag No. 1, Aspendale, Victoria 3195, Australia
5. Izana Atmospheric Research Center, Meteorological State Agency of Spain (AEMET), C/ La Marina, 20, Planta 6, 38071 Santa Cruz de Tenerife, Spain
6. Alfred Wegener Institute for Polar and Marine Research, Am Handelshafen 12, D-27568 Bremerhaven, Germany
7. Environment Canada, Climate Research Division / CCMR, 4905 Dufferin St., Toronto, ON M3H 5T4, Canada