TY - JOUR
T1 - A modeling study of the effect of runoff variability on the effective pressure beneath Russell Glacier, West Greenland
AU - de Fleurian, Basile
AU - Morlighem, Mathieu
AU - Seroussi, Helene
AU - Rignot, Eric
AU - van den Broeke, Michiel R.
AU - Kuipers Munneke, Peter
AU - Mouginot, Jeremie
AU - Smeets, Paul C.J.P.
AU - Tedstone, Andrew J.
PY - 2016/10/1
Y1 - 2016/10/1
N2 - Basal sliding is a main control on glacier flow primarily driven by water pressure at the glacier base. The ongoing increase in surface melting of the Greenland Ice Sheet warrants an examination of its impact on basal water pressure and in turn on basal sliding. Here we examine the case of Russell Glacier, in West Greenland, where an extensive set of observations has been collected. These observations suggest that the recent increase in melt has had an equivocal impact on the annual velocity, with stable flow on the lower part of the drainage basin but accelerated flow above the Equilibrium Line Altitude (ELA). These distinct behaviors have been attributed to different evolutions of the subglacial draining system during and after the melt season. Here we use a high-resolution subglacial hydrological model forced by reconstructed surface runoff for the period 2008 to 2012 to investigate the cause of these distinct behaviors. We find that the increase in meltwater production at low elevation yields a more efficient drainage system compatible with the observed stagnation of the mean annual flow below the ELA. At higher elevation, the model indicates that the drainage system is mostly inefficient and is therefore strongly sensitive to an increase in meltwater availability, which is consistent with the observed increase in ice velocity.
AB - Basal sliding is a main control on glacier flow primarily driven by water pressure at the glacier base. The ongoing increase in surface melting of the Greenland Ice Sheet warrants an examination of its impact on basal water pressure and in turn on basal sliding. Here we examine the case of Russell Glacier, in West Greenland, where an extensive set of observations has been collected. These observations suggest that the recent increase in melt has had an equivocal impact on the annual velocity, with stable flow on the lower part of the drainage basin but accelerated flow above the Equilibrium Line Altitude (ELA). These distinct behaviors have been attributed to different evolutions of the subglacial draining system during and after the melt season. Here we use a high-resolution subglacial hydrological model forced by reconstructed surface runoff for the period 2008 to 2012 to investigate the cause of these distinct behaviors. We find that the increase in meltwater production at low elevation yields a more efficient drainage system compatible with the observed stagnation of the mean annual flow below the ELA. At higher elevation, the model indicates that the drainage system is mostly inefficient and is therefore strongly sensitive to an increase in meltwater availability, which is consistent with the observed increase in ice velocity.
KW - glacier dynamics
KW - ice sheet modeling
KW - modeling
KW - subglacial hydrology
UR - http://www.scopus.com/inward/record.url?scp=84991461433&partnerID=8YFLogxK
U2 - 10.1002/2016JF003842
DO - 10.1002/2016JF003842
M3 - Article (Academic Journal)
AN - SCOPUS:84991461433
SN - 2169-9003
VL - 121
SP - 1834
EP - 1848
JO - Journal of Geophysical Research: Earth Surface
JF - Journal of Geophysical Research: Earth Surface
IS - 10
ER -