A high-resolution record of Greenland mass balance

• Main Authors: McMillan, M, Leeson, A, Shepherd, A, Briggs, K, Armitage, TWK, Hogg, A, Munneke, PK, van den Broeke, M, Noel, B, van de Berg, WJ, Ligtenberg, S, Horwath, M, Groh, A, Muir, A, Gilbert, L
• Format: Article in Journal/Newspaper
• Language: English
• Published: AMER GEOPHYSICAL UNION 2016
• Subjects: Science & Technology; Physical Sciences; Geosciences; Multidisciplinary; Geology; Greenland Ice Sheet; mass balance; altimetry; CryoSat-2; Grace; Sea-level Rise; Regional Climate Model; Time-variable Gravity; Antarctic Ice-sheet; Elevation Change; Radar Altimetry; Surface Melt; Firn; Antarctic; Greenland; Antarc*; glacier; Ice Sheet
• Online Access: https://discovery.ucl.ac.uk/id/eprint/1521743/1/McMillan_et_al-2016-Geophysical_Research_Letters.pdf; https://discovery.ucl.ac.uk/id/eprint/1521743/

We map recent Greenland Ice Sheet elevation change at high spatial (5 km) and temporal (monthly) resolution using CryoSat-2 altimetry. After correcting for the impact of changing snowpack properties associated with unprecedented surface melting in 2012, we find good agreement (3 cm/yr bias) with airborne measurements. With the aid of regional climate and firn modeling, we compute high spatial and temporal resolution records of Greenland mass evolution, which correlate (R = 0.96) with monthly satellite gravimetry and reveal glacier dynamic imbalance. During 2011–2014, Greenland mass loss averaged 269 ± 51 Gt/yr. Atmospherically driven losses were widespread, with surface melt variability driving large fluctuations in the annual mass deficit. Terminus regions of five dynamically thinning glaciers, which constitute less than 1% of Greenland's area, contributed more than 12% of the net ice loss. This high-resolution record demonstrates that mass deficits extending over small spatial and temporal scales have made a relatively large contribution to recent ice sheet imbalance.