1. Chemical Sciences Division Earth System Research Laboratory, National Oceanic and Atmospheric Administration Boulder Colorado USA
2. Cooperative Institute for Research in Environmental Sciences University of Colorado Boulder Colorado USA
3. Center for International Climate and Environmental Research – Oslo (CICERO) Oslo Norway
4. Science and Technology Corporation Boulder Colorado USA
5. Atmospheric, Oceanic and Planetary Physics, Department of Physics University of Oxford Oxford UK
6. Laboratoire des Sciences du Climat et de l'Environnement Gif‐sur‐Yvette France
7. Global Monitoring Division Earth System Research Laboratory, National Oceanic and Atmospheric Administration Boulder Colorado USA