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Persistent flow acceleration within the interior of the Greenland ice sheet
Author(s) -
Doyle Samuel H.,
Hubbard Alun,
Fitzpatrick Andrew A. W.,
As Dirk,
Mikkelsen Andreas B.,
Pettersson Rickard,
Hubbard Bryn
Publication year - 2014
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1002/2013gl058933
Subject(s) - greenland ice sheet , geology , ice sheet , ice stream , groenlandia , elevation (ballistics) , climatology , atmospheric sciences , geomorphology , cryosphere , sea ice , geometry , mathematics
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.