Name
Characterization of the turbulent fluxes and surface melt for two Canadian Rockies glaciers
Date & Time
Wednesday, May 10, 2023, 10:30 AM - 10:45 AM
Description
Turbulent fluxes play a critical role in the energy balance of glaciers and are an important factor to consider when modeling glacier melt. They can be influenced by drainage winds of cold, damp air in layers close to the glacier surface. Melt season meteorology, turbulent fluxes and the resulting surface melt were investigated for the Athabasca and Peyto glaciers in the Canadian Rockies. Profiles of air temperature, humidity and wind speed, in addition to turbulent fluxes measured using eddy-covariance systems, a full radiation budget and snow or ice surface lowering were measured for 13 days in June 2015 on the Athabasca Glacier and intermittently for 14 days in July and August 2008 on Peyto Glacier. At Peyto Glacier, a katabatic wind was detected in 51% of the measurements and only in 31% of the measurements at the Athabasca profile. At both sites, the net radiation (shortwave and longwave) was the largest energy flux, contributing nearly 70% of the energy available for melt. In contrast, the sensible heat flux contributed approximately 30% while the latent heat flux contributed less than 2.5% of the energy available for melt. The turbulent fluxes were simulated using a bulk transfer approach and a katabatic parametrization. The katabatic approach underestimated the turbulent fluxes compared to the eddy covariance measurements, while the bulk transfer approach overestimated them. The sensitivities of these approaches to the aerodynamic roughness length were evaluated in order to improve flux representations.
Location Name
Maple
Full Address
Banff Park Lodge Resort Hotel & Conference Centre
201 Lynx St
Banff AB T1L 1K5
Canada
Abstract
Turbulent fluxes play a critical role in the energy balance of glaciers and are an important factor to consider when modeling glacier melt. They can be influenced by drainage winds of cold, damp air in layers close to the glacier surface. Melt season meteorology, turbulent fluxes and the resulting surface melt were investigated for the Athabasca and Peyto glaciers in the Canadian Rockies. Profiles of air temperature, humidity and wind speed, in addition to turbulent fluxes measured using eddy-covariance systems, a full radiation budget and snow or ice surface lowering were measured for 13 days in June 2015 on the Athabasca Glacier and intermittently for 14 days in July and August 2008 on Peyto Glacier. At Peyto Glacier, a katabatic wind was detected in 51% of the measurements and only in 31% of the measurements at the Athabasca profile. At both sites, the net radiation (shortwave and longwave) was the largest energy flux, contributing nearly 70% of the energy available for melt. In contrast, the sensible heat flux contributed approximately 30% while the latent heat flux contributed less than 2.5% of the energy available for melt. The turbulent fluxes were simulated using a bulk transfer approach and a katabatic parametrization. The katabatic approach underestimated the turbulent fluxes compared to the eddy covariance measurements, while the bulk transfer approach overestimated them. The sensitivities of these approaches to the aerodynamic roughness length were evaluated in order to improve flux representations.
Session Type
Breakout Session