Using digital elevation models to measure the surface and volumetric change of Athabasca Glacier, Alberta, Canada, 1919-1979

The Athabasca Glacier (52˚12\u27N, 117˚14\u27W) located at the Alberta-British Columbia border was studied to quantify its volumetric, area and elevation changes below 2400 m between 1919 and 1979. The data sources consist of maps produced using aerial and terrestrial photogrammetry in the years between 1919 and 1979. The maps were digitized and converted into raster digital elevation models (DEMs), the manipulation of which allowed values of surface and volumetric change to be calculated. These DEMs showed that between 1919 and 1979 the glacier lost 2.344 x 108m3 of volume and receded more than 1 km. Each of the source maps has a precision of vertical estimation associated with the photogrammetric process used to generate it. This imprecision was quantified and used to calculate, display and compare the uncertainty of volume and elevation change measures with the calculated volume and elevation change. The magnitude of uncertainty between maps was often larger than the change measured between the maps. many of the maps used to generate DEMs were used in a previous study to calculate volumetric and elevation change using planimetric methods. The software package which produced the DEMs and calculated output was used to recalculate volumetric change measures using the same methodology for the period 1969-1979. The recalculated results were similar to the planimetric results for that time period. Several other stories of Canadian glacier maps exist. It is recommended that a similar study be carried out using these data