1. a Swedish Meteorological and Hydrological Institute , 601 76 Norrköping, Sweden
2. b Swedish Meteorological and Hydrological Institute, Nya Varvet 31, 421 76 Västra Frölunda, Sweden and Remote Sensing and Ecological Geography group, Department of Physical Geography , Stockholm University , S‐10691 Stockholm, Sweden
3. c Remote Sensing Group, Plymouth Marine Laboratory, Prospect Place , West Hoe , Plymouth PL1 3DH, UK