Changes in Clemenceau Icefield and Chaba Group glaciers, Canada, related to hypsometry, tributary detachment, length–slope and area–aspect relations

Abstract

AbstractWe compiled a detailed glacier inventory of 176 glaciers in the Clemenceau Icefield Group (CIG) and adjacent Chaba Group (CH), Canada, based on 2001 Landsat 7 and 2000–03 ASTER satellite imagery and Natural Resources Canada digital elevation models. We used this inventory to measure length and mass-balance changes and their possible controls. A classification of glacier hypsometry in the form of a hypsometric index was used to assess the sensitivity of different glacier systems to a unit rise in snowline. The altitude and AAR of possible steady-state ELAs was derived using several methods, and was compared to late-summer snowlines of 2001 .We further compared planar glacier area to slope-corrected area, and compared the effects on the shape of the hypsometric curves, on the total glacier area and on the aspect–area distribution. In 2001, CIG had a glaciated area of 271 km2 and had lost 42 km2 since the mid-1980s. CH had a total area of 69 km2 and had lost 28 km2. Average retreat rates are 14 ma–1 for the period 1850–2001 (n=39) and 21 ma–1 for 1986/87–2001 (n=23), indicating accelerated retreat. Larger glaciers and those that experience tributary detachment tend to retreat faster. The difference between planar and slope-corrected glacier areas ranges from 5% to 20%, with a 6% increase for the entire CIG/CH region. The area increase does not change the shape of the hypsometric curves.