Supervised by:

Christophe Kinnard (Regular member)

Research project description

Aerodynamic roughness length and albedo influence on the spacial variability of the glaciological mass balance: case study at Bologna glacier, Canada

IntroductionThe majority of glaciers in Canada are situated in mountains and arctic areas. Thus, these glaciers are difficult to access for doing a regular monitoring. Some glaciological mass balance models are using the interaction between weather conditions and the surface properties. Those are utilized to simulate the evolution of glaciers in response to the climate. The surface properties of a glacier like the roughness and the albedo can strongly influence the ablation processes. However, these two properties are usually assumed constant on a glacier surface. The roughness caused by the presence of crevasses, foliations and ice hummocks can increase the turbulence and the amount of sensible heat in summer that will increase the melt. Being able to measure these variables on a glacier is difficult. That is why it is necessary to develop some indirect methods to measure these variables. ObjectivesThe goal of this study is to use and develop indirect methods to quantify and measure ablation processes (melting and sublimation) and surface conditions on a glacier. More precisely, I will examine the albedo and roughness roles compared to the altitude and the potential solar radiation on the glacier mass balance as assessed by the geodetic and glaciological methods. Study sitesThe study site is the Bologna Glacier in the Northwest Territories in Nahanni National Park. This glacier is the most recent glacier subject to intermittent monitoring since 2008 by the Geological Survey of Canada. Material and methodsThe surface of the Bologna Glacier (17 km2) will be mapped with a drone during a multi-day field campaign. As this glacier has been monitored since 2008, the glacier already has a network of ablation beacons and a digital terrain model (DTM) acquired in 2017. Roughness metrics will be calculated from the topographic surface (drone), and albedo calculated from reflectance orthoimages. The topographic surface mapped during the field campaign for this study will be differentiated from the 2017 DEM to calculate a geodetic mass balance. Following these manipulations, analyzes will be carried out to quantify the effects of albedo, soil roughness, altitude and solar radiation on the geodesic mass balance of the glacier. A roughness parameterization from a coarser resolution DEM will be sought, in order to guide the inclusion of spatial roughness variability in glaciological models. References

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