1. NOAA Earth System Research Laboratory (ESRL), Boulder, Colorado, USA
2. Cooperative Institute for Research in Environmental Sciences (CIRES), University of Colorado, Boulder, Colorado, USA
3. NOAA Pacific Marine Environmental Laboratory, Seattle, Washington, USA
4. Joint Institute for the Study of the Atmosphere and Ocean, University of Washington, Seattle, Washington, USA
5. Department of Chemistry, University of Florence, Sesto Fiorentino, Florence, Italy