1. Institute of Meteorology and Climate Research, Department Troposphere Research Karlsruhe Institute of Technology Karlsruhe Germany
2. Lamont‐Doherty Earth Observatory Columbia University New York New York USA
3. Grantham Institute, Imperial College London London UK
4. Department of Environmental Sciences University of Virginia Charlottesville Virginia USA
5. Department of Atmospheric Science Colorado State University Fort Collins Colorado USA
6. National Center for Atmospheric Research Boulder Colorado USA