Timing and origin of recent regional ice-mass loss in Greenland

• Published in: Earth and Planetary Science Letters
• Main Authors: Sasgen, Ingo, van den Broeke, Michiel, Bamber, J.L.Jonathan L., Rignot, Eric, Sørensen, Louise Sandberg, Wouters, Bert, Martinec, Zdeněk, Velicogna, Isabella, Simonsen, Sebastian Bjerregaard
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2012
• Subjects: Mass balance; Greenland; GRACE; InSAR; RACMO; ICESat; /dk/atira/pure/sustainabledevelopmentgoals/climate_action; name=SDG 13 - Climate Action; Ice Sheet; Sea ice
• Online Access: https://orbit.dtu.dk/en/publications/6a97751c-94a5-4dae-8f68-f41648b098da; https://doi.org/10.1016/j.epsl.2012.03.033

Within the last decade, the Greenland ice sheet (GrIS) and its surroundings have experienced record high surface temperatures (Mote, 2007; Box et al., 2010), ice sheet melt extent (Fettweis et al., 2011) and record-low summer sea-ice extent (Nghiem et al., 2007). Using three independent data sets, we derive, for the first time, consistent ice-mass trends and temporal variations within seven major drainage basins from gravity fields from the Gravity Recovery and Climate Experiment (GRACE; Tapley et al., 2004), surface-ice velocities from Inteferometric Synthetic Aperture Radar (InSAR; Rignot and Kanagaratnam, 2006) together with output of the regional atmospheric climate modelling (RACMO2/GR; Ettema et al., 2009), and surface-elevation changes from the Ice, cloud and land elevation satellite (ICESat; Sørensen et al., 2011). We show that changing ice discharge (D), surface melting and subsequent run-off (M/R) and precipitation (P) all contribute, in a complex and regionally variable interplay, to the increasingly negative mass balance of the GrIS observed within the last decade. Interannual variability in P along the northwest and west coasts of the GrIS largely explains the apparent regional mass loss increase during 2002–2010, and obscures increasing M/R and D since the 1990s. In winter 2002/2003 and 2008/2009, accumulation anomalies in the east and southeast temporarily outweighed the losses by M/R and D that prevailed during 2003–2008, and after summer 2010. Overall, for all basins of the GrIS, the decadal variability of anomalies in P, M/R and D between 1958 and 2010 (w.r.t. 1961–1990) was significantly exceeded by the regional trends observed during the GRACE period (2002–2011).