1. Institute of Low Temperature ScienceHokkaido University Sapporo Japan
2. Graduate School of Environmental ScienceHokkaido University Sapporo Japan
3. Department of Physical GeographyStockholm University Stockholm Sweden
4. Climate and Environmental Physics, Physics Institute and Oeschger Centre for Climate Change ResearchUniversity of Bern Bern Switzerland
5. Centre for Ice and Climate, Niels Bohr InstituteUniversity of Copenhagen Copenhagen Denmark