Stella Bērziņa, ETH Zurich, Zurich, Switzerland, Malcolm J Roberts, Met Office Hadley center for Climate Change, Exeter, United Kingdom, Aaron Wienkers, ETH Zürich, Zürich, Switzerland, Nicolas Gruber, Environmental Physics, Institute of Biogeochemistry and Pollutant Dynamics, ETH Zurich, Zurich, Switzerland and Matthias Munnich, ETH Zurich Swiss Federal Institute of Technology Zurich, Zurich, SWITZERLAND