Applying Flow Line Modelling, and GIS to Reconstruct the Glacier Volume Loss for Athabasca Glacier, Canadian Rockies.

Glaciers respond strongly to small climatic shifts, so records of historical glacier change can be used to reconstruct past climate. In turn, understanding glacier sensitivity to climate variability is important for regional water resources and for projecting glacier response to ongoing climate change. We develop an enhanced flow-line model of glacier dynamics to simulate the past and future extent of glaciers in the Canadian Rocky Mountains, with the aim of coupling this model within larger scale regional climate models of glacier response to climate change. Longitudinal stress and shape factors are introduced to provide a more complete treatment of glacier dynamics. This presentation focuses on glacier volume reconstructions from the Little Ice Age (LIA) to present for Athabasca Glacier, Alberta, Canada. Athabasca Glacier, located on the continental divide of the Canadian Rocky Mountains, is the second largest outlet of the Columbia Icefield. With the availability of SPOT 5 imagery, Digital Elevation Model and GIS Arc Hydro tool, ice catchment properties- glacier width and LIA moraines have been extracted using automated procedures. Simulating backwards in time from present day to 1850, we model glacier thickness, volume and mass change and examine different climate and glaciological parametrizations that are able to give good reconstructions of LIA ice extent. Mass balance modelling is based on modelled and observed temperature records from the region, along with the winter Pacific Decadal Oscillation index as a precipitation proxy. Dated lateral and terminal moraines provide geological control on the LIA maximum glacier geometry. Reconstructions of glacier mass change will inform estimates of meltwater run off over the historical period and model calibration from the LIA reconstruction will aid in future projections of the effects of climate change on glacier recession. Furthermore, the model developed will be effective for further future studies with ensembles of glaciers.