Recurring dynamically induced thinning during 1985-2010 on Upernavik Isstrøm, West Greenland

• Published in: Journal of Geophysical Research: Earth Surface
• Main Authors: Khan, Shfaqat Abbas, Kjær, Kurt H., Korsgaard, Niels Jákup, Wahr, John, Joughin, Ian R., Timm, Lars H., Bamber, Jonathan L, van den Broeke, Michiel R., Stearns, Leigh A., Hamilton, Gordon S., Csatho, Bea M., Nielsen, Karina, Hurkmans, Ruud, Babonis, Greg
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2013
• Subjects: Airborne Topographic Mapper; Greenland; Ice Sheet; Upernavik
• Online Access: https://curis.ku.dk/portal/da/publications/recurring-dynamically-induced-thinning-during-19852010-on-upernavik-isstroem-west-greenland(a01a5598-3138-4f98-8c48-bd59d170d0fd).html; https://doi.org/10.1029/2012JF002481

Many glaciers along the southeast and northwest coasts of Greenland have accelerated, increasing the ice sheet’s contribution to global sea-level rise. Here, we map elevation changes on Upernavik Isstrøm (UI), West Greenland, during 2003-2009 using high-resolution Ice, Cloud and land Elevation Satellite (ICESat) laser altimeter data supplemented with altimeter surveys from NASA’s Airborne Topographic Mapper (ATM) during 2002-2010. To assess thinning prior to 2002, we analyze aerial photographs from 1985. We document at least two distinct periods of dynamically-induced ice loss during 1985-2010 characterized by a rapid retreat of the calving front, increased ice speed and lowering of the ice surface. The first period occurred prior to 1991, while the latter occurred during 2005-2009. Analyses of air and sea surface temperature suggest a combination of relatively warm air and ocean water as a potential trigger for the dynamically-induced ice loss. We estimate a total catchment-wide ice mass loss of UI caused by the two events of 72.3 +/- 15.8 Giga-ton during 1985-2010, while the total melt induced ice mass loss during this same period is 19.8 +/ 2.8 Gt. Thus, 79 % of the total ice mass loss of the UI catchment was caused by ice dynamics, indicating the importance of including dynamically-induced ice loss in the total mass change budget of the Greenland ice sheet.