TY - JOUR
T1 - An increase in crevasse extent, West Greenland
T2 - Hydrologic implications
AU - Colgan, William
AU - Steffen, Konrad
AU - McLamb, W. Scott
AU - Abdalati, Waleed
AU - Rajaram, Harihar
AU - Motyka, Roman
AU - Phillips, Thomas
AU - Anderson, Robert
PY - 2011/9/28
Y1 - 2011/9/28
N2 - We compare high-resolution 1985 and 2009 imagery to assess changes in crevasse extent in the Sermeq Avannarleq ablation zone, West Greenland. The area occupied by crevasses >2 m wide significantly increased (13 4%) over the 24-year period. This increase consists of an expansion of existing crevasse fields, and is accompanied by widespread changes in crevasse orientation (up to 45). We suggest that a combination of ice sheet thinning and steepening are responsible for the increase in crevasse extent. We examine the potential impact of this change on the hydrology of the ice sheet. We provide a first-order demonstration that moulin-type drainage is more efficient in transferring meltwater fluctuations to the subglacial system than crevasse-type drainage. As enhanced basal sliding is associated with meltwater "pulses", an increase in crevasse extent can therefore be expected to result in a net decrease in basal sliding sensitivity. An increase in crevasse extent may also accelerate cryo-hydrologic warming and enhance surface ablation.
AB - We compare high-resolution 1985 and 2009 imagery to assess changes in crevasse extent in the Sermeq Avannarleq ablation zone, West Greenland. The area occupied by crevasses >2 m wide significantly increased (13 4%) over the 24-year period. This increase consists of an expansion of existing crevasse fields, and is accompanied by widespread changes in crevasse orientation (up to 45). We suggest that a combination of ice sheet thinning and steepening are responsible for the increase in crevasse extent. We examine the potential impact of this change on the hydrology of the ice sheet. We provide a first-order demonstration that moulin-type drainage is more efficient in transferring meltwater fluctuations to the subglacial system than crevasse-type drainage. As enhanced basal sliding is associated with meltwater "pulses", an increase in crevasse extent can therefore be expected to result in a net decrease in basal sliding sensitivity. An increase in crevasse extent may also accelerate cryo-hydrologic warming and enhance surface ablation.
UR - http://www.scopus.com/inward/record.url?scp=80053020177&partnerID=8YFLogxK
U2 - 10.1029/2011GL048491
DO - 10.1029/2011GL048491
M3 - Article
AN - SCOPUS:80053020177
VL - 38
JO - Geophysical Research Letters
JF - Geophysical Research Letters
SN - 0094-8276
IS - 18
M1 - L18502
ER -