1. Norwegian Polar Institute; Tromsø Norway
2. Cryospheric Sciences Laboratory, Earth System Science Interdisciplinary Center; University of Maryland; College Park Maryland USA
3. Goddard Space Flight Center; National Aeronautics and Space Administration; Greenbelt Maryland USA
4. Alfred Wegener Institute; Helmholtz Centre for Polar and Marine Research; Potsdam Germany
5. Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research; Bremerhaven Germany