M. Demuth

Recent volume and area changes of Kaskawulsh Glacier, Yukon, Canada

Recent surface elevation changes of Kaskawulsh Glacier, Yukon, Canada, are quantified by comparing an air-photo derived DEM from 1977 and airborne lidar measurements from 1995, 2000 and 2007. Surface-area changes are assessed using historical aerial photography from 1956 and satellite imagery from 1977 to 2007. Combined, these measurements provide some of the first detailed records of volume change of a large Yukon glacier. Between 1977 and 2007, Kaskawulsh Glacier underwent a decrease in area of 1.53% and a decrease in volume of 3.27-5.94 km 3 w.e.). The terminus also retreated by 655 m over the period 1956-2007. There was relatively minor volume change over the period 1977- 95 (<+0.01 km 3 w.e. a -1 ), while over the periods 1995-2000 and 2000-07 volume losses occurred at a relatively constant rate of -0.51 and -0.50 km 3 a -1 w.e., respectively. Since 1995, thinning has been prominent throughout the ablation zone, while relative stability and even slight thickening has occurred in the accumulation zone. These findings are similar to those recently observed at other nearby Alaskan glaciers.

Applications of airborne LiDAR mapping in glacierised mountainous terrain

Discusses logistics and applications of the first complete airborne scanning LiDAR survey of a glacierised mountain basin. The survey was conducted over a 25/spl times/6 km area with ground height variation from 1800 m asl to 3400 m asl. The resolution of survey points on the ground varied from 1 per sq metre to around 1 per 4 sq metres, depending on elevation. Correspondence from swath to swath is very good despite the extreme nature of the topography and individual ground laser heights are accurate to within 20 cm. Glaciological applications for the high-resolution digital elevation data are outlined. Special attention is paid to radiation loading model-scaling issues.

Mapping changing temperature patterns over a glacial moraine using oblique thermal imagery and lidar

Due to access difficulties in active alpine moraine environments, it can be challenging to accurately map and quantify debris cover and ice-core extent. To aid in identifying the presence and extent of ice-cored moraine, a non-invasive method of mapping spatial and temporal moraine temperature patterns using a light detection and ranging (lidar) digital elevation model (DEM) and sequences of oblique thermal imagery was evaluated. A procedure of lidar DEM-based orthorectification of thermal images collected through time from different locations enabled maps of temperature change to be generated and thermal signatures plotted. Although no exposed ice was visible on the moraine slope studied, the presence of shallow ice core beneath the debris-covered surface was inferred in areas of cooler temperatures during daylight solar heating and rapid thermal decay after sunset. It is presumed that this apparent increased heat loss in some areas of the moraine is being used to drive internal melt processes. It is believed that such temporal thermal imaging at high repetition frequency will aid in remotely mapping the presence of buried ice and, with the combination of energy balance data and further field validation, could enable the estimation of debris cover depth.