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DOI : 10.1038/ngeo737

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Nature geoscience 3, 2 (2010) 92-95

Contribution of Alaskan glaciers to sea level rise derived from satellite imagery

Etienne Berthier 1, Eric Schiefer 2, Garry K. C. Clarke 3, Brian Menounos 4, Frédérique Rémy 1

(2010)

Over the last 50 years, retreating glaciers and ice caps (GIC) contributed 0.5 mm/yr to sea level rises (SLR), and one third is believed to originate from ice masses bordering the Gulf of Alaska. However, these estimates of ice wastage in Alaska are based on methods that measure a limited number of glaciers and extrapolate the results to estimate ice loss for the many thousands of others. How these methods capture the complex pattern of decadal elevation changes at the scale of individual glacier and mountain range is unclear. Here, combining a comprehensive glacier inventory with elevation changes derived from sequential digital elevation models (DEMs), we found that, between 1962 and 2006, Alaskan glaciers lost 41.9 ± 8.6 km**3/yr water equivalent (w.e.) and contributed 0.12±0.02 mm/yr to SLR. Our ice loss is 34% lower than previous estimates. Reasons for our lower values include the higher spatial resolution of our glacier inventory and the reduction of ice thinning under debris and at the glacier margins which were not resolved in earlier work. Estimates of mass loss from GIC in other mountain regions could be subject to similar revisions.

1 :	Laboratoire d'études en Géophysique et océanographie spatiales (LEGOS)
	CNRS : UMR5566 – Institut de recherche pour le développement [IRD] – CNES – Observatoire Midi-Pyrénées – INSU – Université Paul Sabatier [UPS] - Toulouse III
2 :	Department of Geography, Planning and Recreation (NAU)
	Northern Arizona University
3 :	Earth and Ocean Sciences (EOS)
	University of British Columbia
4 :	Geography Program and Natural Resources Environmental Studies Institute (UNBC)
	University of Northern British Columbia

Domaine

:

Planète et Univers/Sciences de la Terre/Océanographie

Mots Clés : Glacier – Alaska – Sea level rise – satellite – ASTER – SPOT5

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