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TitleHow well is firn densification represented by a physically-based multilayer model? Model evaluation for the Devon Ice Cap, Nunavut, Canada
AuthorGascon, G; Sharp, M; Burgess, D; Bezeau, P; Bush, A B G; Morin, S; Lafaysse, M
SourceJournal of Glaciology vol. 60, no. 222, 2014 p. 1-11,
Alt SeriesEarth Sciences Sector, Contribution Series 20130338
PublisherAmerican Geophysical Union
Mediapaper; on-line; digital
File formatpdf
NTS48H/03; 48H/06
AreaDevon Island
Lat/Long WENS-83.0000 -82.1667 75.4167 75.0833
Subjectssurficial geology/geomorphology; geophysics; glaciology; glaciation; climate, arctic; climate; vegetation; Devon Ice Cap; Cenozoic; Quaternary
Illustrationstables; photographs; profiles
ProgramEssential Climate Variable Monitoring, Climate Change Geoscience
AbstractEvaluation of how accurately snowpack models can capture hydrological processes in firn is critical to determining how well they will simulate future glacier mass-balance changes. Here we compare simulations using the Crocus snowpack model with the evolving firn stratigraphy recorded in 14 cores drilled at four elevations in the accumulation zone of Devon Ice Cap, Canada, during the 2004-12 period of rapid summer warming. Simulations were forced with a combination of surface observations and reanalysis data. Simulations resulted in positive model bias in near-surface density, and negative bias in density at depth compared to observations. Results point to the importance of incorporating heterogeneous percolation in firn in order to improve the representation of meltwater flow, better reproduce observed firn density and temperature profile evolution, and improve simulations of glacier mass balance during periods of climate warming.
Summary(Plain Language Summary, not published)
Recent warming at high northern latitudes has not only enhanced mass loss from ice caps through increasing ice melt and runoff at lower elevations (<1300m a.s.l.), but has also increased density of near surface firn across high elevation (>1300m a.s.l.) sectors of these ice caps. An important consequence of firn densification is that it promotes surface run-off from increasingly larger areas of glaciated terrain, hence increasing the amount of water flux to oceans during summer melt events. This study uses field data from the Devon ice cap, Nunavut collected between 2004 and 2012 to validate a firn densification model. Good correspondence between model results and observed ice layer development suggest that such models can be useful for predicting rates of mass loss due to surface melting from polar ice caps under climate warming scenarios.