[1] Univ Ctr Svalbard, N-9170 Longyearbyen, Norway
[2] Univ St Andrews, Sch Geog & Geosci, St Andrews KY16 9AL, Fife, Scotland
[3] Univ Zurich, Geog Inst, CH-8057 Zurich, Switzerland
[4] Tech Univ Dresden, Inst Kartog, D-01069 Dresden, Germany
[5] URS Scott Wilson, Edinburgh EH3 7EN, Midlothian, Scotland
[6] Univ Texas Austin, Inst Geophys, Austin, TX 78758 USA
[7] Swansea Univ, Coll Sci, Dept Geog, Swansea SA2 8PP, W Glam, Wales
[8] Univ Innsbruck, Inst Meteorol & Geophys, A-6020 Innsbruck, Austria
[9] Univ Leeds, Sch Geog, Leeds LS2 9JT, W Yorkshire, England
[10] Univ London Imperial Coll Sci Technol & Med, Dept Phys, London SW7 2AZ, England
[11] Univ Aberdeen, Aberdeen AB24 3UF, Scotland