TY - JOUR
T1 - Spatio-temporal variability in elevation changes of two high-Arcticvalley glaciers
AU - Barrand, N.E.
AU - James, T.D.
AU - Murray, T.
N1 - Copyright 2011 Elsevier B.V., All rights reserved.
PY - 2010/12/1
Y1 - 2010/12/1
N2 - Uncertainties in estimates of glacier and ice-cap contribution to sea-level rise exist in part due to poor quantification of mass-balance errors, particularly those resulting from extrapolation ofsparse measurements. Centre-line data are often assumed to be representative of the glacier as awhole, with little attention paid to extrapolation errors or their effect on mass-balance estimates. Here we present detailed digital elevation model (DEM) measurements of glacier-wide elevation changes over the last ̃40 years at two glaciers on Svalbard, Norwegian Arctic. Austre Brøggerbreen and Midtre Lovénbreen are shown to have lost 27.54±0.98 and 9.65±0.76×10 m of ice, respectively, between 1966 and 2005, findings that we relate to trends in average summer air temperatures and winter accumulation. These volume losses correspond to geodetic balances of -0.58±0.03 and -0.41±0.03mw.e. a , respectively. Our analysis revealed high spatial complexity in patterns of elevation change, varying between glaciers, between measurement intervals and within and between elevation bins. Balances from extrapolated centre-line geodetic data were the same (within errors) as those from full-coverage DEM differencing in the majority of comparisons, yet significantly underestimated balance in three instances. Additionally, field mass balance from centre-line ablation stake data underestimated balances from full-coverage geodetic measurements during three of six measurement periods. These findings may support the hypothesis that field measurements underestimate Svalbard glacier mass loss, at least partly as a result of the failure of centre-line measurements to account for glacier-wide variations in ablation. Our results demonstrate the importance of deriving accurate interpolation functions and constraining extrapolation errors from sparse measurements.
AB - Uncertainties in estimates of glacier and ice-cap contribution to sea-level rise exist in part due to poor quantification of mass-balance errors, particularly those resulting from extrapolation ofsparse measurements. Centre-line data are often assumed to be representative of the glacier as awhole, with little attention paid to extrapolation errors or their effect on mass-balance estimates. Here we present detailed digital elevation model (DEM) measurements of glacier-wide elevation changes over the last ̃40 years at two glaciers on Svalbard, Norwegian Arctic. Austre Brøggerbreen and Midtre Lovénbreen are shown to have lost 27.54±0.98 and 9.65±0.76×10 m of ice, respectively, between 1966 and 2005, findings that we relate to trends in average summer air temperatures and winter accumulation. These volume losses correspond to geodetic balances of -0.58±0.03 and -0.41±0.03mw.e. a , respectively. Our analysis revealed high spatial complexity in patterns of elevation change, varying between glaciers, between measurement intervals and within and between elevation bins. Balances from extrapolated centre-line geodetic data were the same (within errors) as those from full-coverage DEM differencing in the majority of comparisons, yet significantly underestimated balance in three instances. Additionally, field mass balance from centre-line ablation stake data underestimated balances from full-coverage geodetic measurements during three of six measurement periods. These findings may support the hypothesis that field measurements underestimate Svalbard glacier mass loss, at least partly as a result of the failure of centre-line measurements to account for glacier-wide variations in ablation. Our results demonstrate the importance of deriving accurate interpolation functions and constraining extrapolation errors from sparse measurements.
UR - http://www.scopus.com/inward/record.url?partnerID=yv4JPVwI&eid=2-s2.0-78349310844&md5=c6f2e6da635380a826bb667d838f7abc
U2 - 10.3189/002214310794457362
DO - 10.3189/002214310794457362
M3 - Article
AN - SCOPUS:78349310844
SN - 0022-1430
VL - 56
SP - 771
EP - 780
JO - Journal of Glaciology
JF - Journal of Glaciology
IS - 199
ER -