1. UNI Research AS; Bergen Norway
2. Bjerknes Centre for Climate Research; Bergen Norway
3. Department of Earth Science; University of Bergen; Bergen Norway
4. Geophysical Institute; University of Bergen; Bergen Norway
5. Department of Atmospheric Sciences; University of Washington; Seattle Washington USA
6. Laboratoire des Sciences du Climat et de l'Envionnement, CEA/CNRS/UVSQ; Gif-sur-Yvette France