1. Cooperative Institute for Research in Environmental Sciences; University of Colorado Boulder; Boulder Colorado USA
2. Geological Survey of Denmark and Greenland; Copenhagen Denmark
3. Department of Geosciences and Earth and Environmental Systems Institute; The Pennsylvania State University; University Park Pennsylvania USA
4. Snow and Landscape Research; Swiss Federal Institute for Forest; Birmensdorf Switzerland
5. Swiss Federal Institute of Technology; Zürich Switzerland
6. École Polytechnique Federal de Lausanne; Lausanne Switzerland