Airborne and spaceborne DEM - and laser altimetry - derived surface elevation and volume changes of the Bering Glacier system , Alaska , USA , and Yukon , Canada , 1972 – 2006

Using airborne and spaceborne high-resolution digital elevation models and laser altimetry, we present estimates of interannual and multi-decadal surface elevation changes on the Bering Glacier system, Alaska, USA, and Yukon, Canada, from 1972 to 2006. We find: (1) the rate of lowering during 1972–95 was 0.9 0.1ma; (2) this rate accelerated to 3.0 0.7ma during 1995–2000; and (3) during 2000–03 the lowering rate was 1.5 0.4ma. From 1972 to 2003, 70% of the area of the system experienced a volume loss of 191 17 km, which was an area-average surface elevation lowering of 1.7 0.2ma. From November 2004 to November 2006, surface elevations across Bering Glacier, from McIntosh Peak on the south to Waxell Ridge on the north, rose as much as 53m. Up-glacier on Bagley Ice Valley about 10 km east of Juniper Island nunatak, surface elevations lowered as much as 28m from October 2003 to October 2006. NASA Terra/MODIS observations from May to September 2006 indicated muddy outburst floods from the Bering terminus into Vitus Lake. This suggests basal–englacial hydrologic storage changes were a contributing factor in the surface elevation changes in the fall of 2006.