1. Department of Earth and Atmospheric Sciences; University of Alberta; Edmonton Alberta T6G 2E3 Canada
2. Bristol Glaciology Centre, School of Geographical Sciences; University of Bristol; Bristol BS8 1SS UK
3. Department of Geography; University of Otago; P.O. Box 56 Dunedin 9054 New Zealand
4. School of Earth Sciences; The Ohio State University at Marion; 384B Morrill Hall, 1465 Mount Vernon Ave Marion OH 43302 USA
5. School of Earth and Ocean Sciences; Cardiff University; Cardiff CF10 3AT UK