CGRG Bibliography of Canadian Geomorphology
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Author : Ainslie, B.; Tennant, C.; Menounos, B.; and Jackson, P.
Date : 2010.
Title : Fifty years of area and volume change of Tiedemann and Klinaklini glaciers, southern Coast Mountains, British Columbia, Canada.
Publication : CMOS-CGU Ottawa 2010. 44th Annual CMOS Congress, 36th Annual Scientific Meeting of CGU, 3rd Joint CMOS-CGU Congress. May 31-June 4, 2010. Ottawa, Ontario.
Issue :
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Abstract
The southern Coast Mountains contain 28% of the total ice- covered area in British Columbia, and previous research indicates substantial area and volume losses from these mountains during the period 1985-1999. Longer records of glacier fluctuations are required, however, to assess whether these observed changes are unusual in the context of the historical record. To extend this record backwards and forwards in time, we calculated area, elevation, and volume change of Tiedemann and Klinaklini glaciers using glacier extents and digital elevation models (DEMs) from aerial photographs and ASTER satellite imagery over the period 1949 to 2009. We differenced older extents and DEMs from more recent ones to obtain changes in area and elevation which we used to calculate volume loss. Tiedemann and Klinaklini glaciers lost 10% of their area over the observation period. Klinaklini Glacier experienced the highest rates of thinning between 1986 and 2000 similar to other glaciers in the western North America. From 1970 to 2000, Klinaklini Glacier thinned 45 ± 0.1 m and lost 22 km3. Between 2000 and 2006, no detectable change in the glacier’s surface elevation or volume (1.1 ± 1.4 km3) was observed. From 1946 to 2000, Tiedemann Glacier thinned 12 ± 0.2 m and lost 0.9 ± 0.7 km3 of ice. One factor that explains the lower observed thinning and volume loss of Tiedemann Glacier is the heavy debris cover that shrouds its ablation area. Similar to Klinaklini, Tiedemann Glacier experienced no detectable volume change (0.6 ± 0.4 km3) between 2000 and 2006. Sequential DEM analysis produced from medium-scale aerial photography for Tiedemann Glacier for the period 2005-2009 indicates that the glacier has thickened at intermediate elevations. The mean surface elevation change for Tiedemann Glacier over the period 2005-2009 is -0.11 ± 0.11 m. Using a mesoscale atmospheric model (RAMS), we dynamically downscaled temperature and precipitation to the glacier locations to assess the climatic factors that could account for the observed changes in area and volume. After correcting for elevation differences and model biases, the model temperature outputs were used to drive a degree-day ablation model, which was combined with model precipitation to calculate volume changes. Work is underway to compare volume change determined through both approaches and to assess the regional extent of the de-accelerated volume loss in first decade of the 21st century.
Bibliography of Canadian Geomorphology