Satellite-derived volume loss rates and glacier speeds for the Juneau Icefield, Alaska

• Main Authors: Melkonian, Andrew K., Willis, Michael J., Pritchard, Matthew E.
• Other Authors: University of North Carolina at Chapel Hill
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2014
• Subjects: Satellite observation; North America; Glacier variation; digital elevation models; Radar observation; X band; Flow velocity; polar regions; cartography; Loss rate; Ice flow; Advanced spaceborne thermal emission and reflection radiometer; Observation radar; Arctic region; Space remote sensing; Subpolar zone; Terra satellite; interferometry; Alaska; high resolution; Radar remote sensing; radiometry; ice fields; C band; United States; Arctic; Juneau Icefield; glacier; Journal of Glaciology
• Online Access: https://doi.org/10.17615/ksd6-7663; https://cdr.lib.unc.edu/downloads/vq27zx73d?file=thumbnail; https://cdr.lib.unc.edu/downloads/vq27zx73d

Abstract We provide a high-resolution map of elevation change rates at the Juneau Icefield (JIF), southeastern Alaska, in order to quantify its contribution to sea-level rise between 2000 and 2009/2013. We also produce the first high-resolution map of ice speeds at the JIF, which we use to constrain flux and look for acceleration. We calculate using stacked digital elevation models (DEMs) from the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) instrument and the Shuttle Radar Topography Mission (SRTM), taking into account SRTM C-band penetration via comparison with SRTM X-band elevations. Overall, the JIF is losing mass less rapidly (0.13 ± 0.12 m w.e. a –1 ) than other Alaskan icefields (0.79 m w.e. a –1 ). We determine glacier speeds using pixel-tracking on optical image pairs acquired from 2001 to 2010 by ASTER, from radar image pairs acquired between 2007 and 2011 and from radar interferometry in 1995. We detect seasonal speed variations but no interannual acceleration, ruling out dynamics as the cause of the observed thinning. Thinning must therefore be due to the documented warming in the region. Flux measurements confirm this for Mendenhall Glacier, showing that calving constitutes only 2.5–5% of mass loss there.