1. Meteorology and Air Quality; Wageningen University; Wageningen The Netherlands
2. NOAA Earth System Research Laboratory; Boulder Colorado USA
3. CIRES; University of Colorado; Boulder Colorado USA
4. National Snow and Ice Data Center; University of Colorado; Boulder Colorado USA
5. Department of Atmospheric Science; Colorado State University; Fort Collins Colorado USA
6. INSTAAR; University of Colorado; Boulder Colorado USA
7. IMAU; Utrecht University; Utrecht The Netherlands