Abby Roat ’22
Research Collaborators: Trevor Hillebrand, Matthew Hoffman
Faculty Collaborator: Trevor Hillebrand, Geology
In the past two decades Humboldt Glacier (HG) in northern Greenland has experienced rapid retreat, the cause of which is not well understood. Previous models, driven by ocean temperature and glacier-averaged subglacial discharge, indicate limited roles of subglacial melting on recent retreat. Here we assess the extent to which spatially-varying subglacial discharge, including from subglacial channels, could localize submarine melting in key areas. We model winter and summer subglacial discharge rates at HG using the subglacial hydrology component of the MPAS-Albany Land Ice model, which are then used to calculate submarine melt rates. Winter conditions only use melting at the base of the glacier as the input while summer simulations add summertime runoff. On average, our model predicts a 5±5% lower mean annual melt rate and an 8±7% lower end-of-summer melt rate than previous estimates. However, our model predicts melt rates >10% higher than previous estimates along the northern section of the glacier terminus near the large trough where HG has been experiencing its fastest retreat since the 1990s. In forthcoming experiments, we will quantify the sensitivity of model results to channelized and distributed hydraulic conductivity and tune these parameters to match observed subglacial meltwater plume locations.