Speaker: Dr. Christine Dow, Department of Geography and Environmental Management
Title: “The hidden world of subglacial hydrology”
Date: April 17th, 2019, 2:30-3:30 PM
Location: Rm. 225, Second Floor of Mitchell Hall
Refreshments will be provided (In interest of sustainability, we encourage everyone to bring their own reusable coffee/drink mugs if possible!)
Abstract
How do we know what is going on underneath glaciers and ice sheets? These are some of the most inaccessible places in the world yet have a vital role to play in the flow speed of the overlying ice, and therefore in rates of future sea level rise. Water that flows at the base of ice bodies can spread out, become highly pressurized, and cause ice acceleration. However, with enough water input, large channels can melt into the overlying ice and poach nearby water, causing an increase of friction at the ice base and corresponding ice deceleration. This relationship is known and understood for Alpine and, to some extent, Greenlandic glacier systems where basal hydrology is primarily driven by water inputs from the ice surface during the summer melt season. Antarctica, in contrast, operates only with water produced in situ at the base of the ice and is therefore a much more constricted, and less well-understood system.
I will present results from the finite element Glacier Drainage System (GlaDS) model, which I have applied to examine subglacial drainage systems in regions such as Totten Glacier in East Antarctica. I compare these results with aerial geophysical data and measured ice shelf melt rates to assess how well the model is performing. The primary model outputs include water thickness, water pressure and flux from the grounded ice into the ocean. Given that Totten Glacier catchment holds ~3.5m of sea level equivalence, determining the controls on ice dynamics in this region is particularly important.