TY - JOUR
T1 - Persistent flow acceleration within the interior of the Greenland ice sheet
AU - Doyle, Samuel H.
AU - Hubbard, Alun
AU - Fitzpatrick, Andrew A.W.
AU - van As, Dirk
AU - Mikkelsen, Andreas B.
AU - Pettersson, Rickard
AU - Hubbard, Bryn
PY - 2014/2/16
Y1 - 2014/2/16
N2 - We present surface velocity measurements from a high-elevation site located 140 km from the western margin of the Greenland ice sheet, and ~ 50 km into its accumulation area. Annual velocity increased each year from 51.78 ± 0.01 m yr-1 in 2009 to 52.92 ± 0.01 m yr-1 in 2012 - a net increase of 2.2%. These data also reveal a strong seasonal velocity cycle of up to 8.1% above the winter mean, driven by seasonal melt and supraglacial lake drainage. Sole et al. (2013) recently argued that ice motion in the ablation area is mediated by reduced winter flow following the development of efficient subglacial drainage during warmer, faster, summers. Our data extend this analysis and reveal a year-on-year increase in annual velocity above the equilibrium line altitude, where despite surface melt increasing, it is still sufficiently low to hinder the development of efficient drainage under thick ice. Key Points Ice flow in the accumulation area accelerated year-on-year between 2009 and 2012 The acceleration correlates with the inland expansion of supraglacial lakes This dynamic response contrasts with observations from the ablation zone
AB - We present surface velocity measurements from a high-elevation site located 140 km from the western margin of the Greenland ice sheet, and ~ 50 km into its accumulation area. Annual velocity increased each year from 51.78 ± 0.01 m yr-1 in 2009 to 52.92 ± 0.01 m yr-1 in 2012 - a net increase of 2.2%. These data also reveal a strong seasonal velocity cycle of up to 8.1% above the winter mean, driven by seasonal melt and supraglacial lake drainage. Sole et al. (2013) recently argued that ice motion in the ablation area is mediated by reduced winter flow following the development of efficient subglacial drainage during warmer, faster, summers. Our data extend this analysis and reveal a year-on-year increase in annual velocity above the equilibrium line altitude, where despite surface melt increasing, it is still sufficiently low to hinder the development of efficient drainage under thick ice. Key Points Ice flow in the accumulation area accelerated year-on-year between 2009 and 2012 The acceleration correlates with the inland expansion of supraglacial lakes This dynamic response contrasts with observations from the ablation zone
KW - Global Positioning System
KW - Greenland Ice Sheet
KW - Ice sheet dynamics
UR - http://www.scopus.com/inward/record.url?scp=84893866282&partnerID=8YFLogxK
U2 - 10.1002/2013GL058933
DO - 10.1002/2013GL058933
M3 - Article
SN - 0094-8276
VL - 41
SP - 899
EP - 905
JO - Geophysical Research Letters
JF - Geophysical Research Letters
IS - 3
ER -