9:30 AM - 9:45 AM
[ACG31-13] Surface elevation change of Bowdoin and Tugto Glacier in northwestern Greenland
We measured the surface elevation over the glacier on August 20, 2007 and September 4, 2010, by analyzing Advanced Land Observing Satellite (ALOS), Panchromatic remote-sensing Instrument for Stereo Mapping (PRISM) images. We also measured surface elevation on bedrock in the eastern flank of Bowdoin Glacier by using the global positioning system on July 18, 2014. We calibrated the satellite derived elevation data with our field measurements, and generated a DEM for each year with a 25 m grid mesh. The DEMs were compared to calculate recent glacier elevation change. Mean surface elevation change for on Bowdoin Glacier increases downglacier from -13 to -20 m, whereas that in Tugto Glacier is spatially uniform (-11 to -12 m). The mean elevation change in Bowdoin Glacier is significantly greater than those observed on ice caps in the region, and similar to those reported for other marine-terminating outlet glaciers in northwestern Greenland. Ice flow velocity increases downglacier in Bowdoin Glacier, whereas no significant gradient of ice velocity was measured in Tugto Glacier. We suggest that a certain portion of the thinning in Bowdoin Glacier was due to stretching flow enhanced by acceleration of ice flow. Our study demonstrate that calving Bowdoin Glacier is losing more ice than land-terminating Tugto Glacier, which suggests the importance of ice dynamics and/or ice-ocean interaction in the ice mass loss in Greenland.