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TitreSummer melt rates on Penny Ice Cap, Baffin Island: Past and recent trends and implications for regional climate
AuteurZdanowicz, C; Smetny-Sowa, A; Fisher, D; Schaffer, N; Copland, L; Eley, J; Dupont, F
SourceJournal of Geophysical Research, Earth Surface vol. 117, issue F2, 2012 p. F02006, (Accès ouvert)
Séries alt.Secteur des sciences de la Terre, Contribution externe 20110335
Documentpublication en série
Mediapapier; en ligne; numérique
SNRC26I; 16L
Régionîle de Baffin
Lat/Long OENS -66.5000 -64.0000 67.0000 66.0000
Sujetsclimat arctique; effets climatiques; glace; concentration de glace; échantillons carrotés; analyse de carottes; mouvement de masse; Calotte glaciaire de Penny ; Nature et environnement
Illustrationscartes de localisation; histogrammes; graphiques; échelles stratigraphiques; graphiques; tableaux
ProgrammeGéosciences de changements climatiques, Gestionaire de programme - sciences de changements climatiques
Diffusé2012 04 10
Résumé(disponible en anglais seulement)
At a latitude of 66 N, Penny Ice Cap on Baffin Island is the southernmost large ice cap in the Canadian Arctic. Here we present a synthesis of local climatological observations, surface mass balance measurements and proxy climate data from cores drilled on the ice cap over five decades (1953 to 2011). We find that since the late 1980s, Penny Ice Cap has entered a phase of enhanced melt rates related to rising summer and winter air temperatures across the eastern Arctic. Surface melt rates at the summit of the ice cap are now close to 100 %, and comparable to those last experienced more than 3000 years ago. Enhanced surface melt, water percolation and refreezing have led to a downward transfer of latent heat that has raised the subsurface firn temperature by ~10 C (at 10 m depth) since the mid-1990s. This process may accelerate further meltdown of the ice cap by pre-conditionning the firn for the ensuing melt season. The recent warming in the Baffin regiin has been larger in winter but more regular in summer, and observations on Penny Ice Cap suggest that is has been relatively uniform over an elevation range of ~2 km. Our findings are consistent with trends in glacier mass wastage in the Canadian High Arctic and with regional sea-ice cover reduction, reinforcing the view that the Arctic appears to be reverting back to a thermal state not seen in millennia.