Modeling Rapid Lake Drainage in Glaciers
Due to recent warming, the Greenland Ice Sheet has undergone a number of dramatic changes
including an increase in the amount of surface meltwater and an increase in iceberg
calving rates. These changes are in turn responsible for changes in the dynamics of
the ice sheet. Understanding the physical processes by which meltwater and calving
affect glacier dynamics is therefore crucial to being able to predict the future of large
ice masses like the Greenland Ice Sheet. One process in particular that deserves attention
is the drainage of surface meltwater lakes to the base of the ice sheet, thereby potentially
lubricating the bed. Sometimes this
drainage is rapid, implying turbulent flow of water and an ice sheet response that
involves elastic behavior. This drainage can be understood by jointly modeling the flow
of water, the expansion of a subglacial crack that fills with water, and the deformation
of the ice itself (Tsai and Rice, 2010; 2012). See publications for more details.
The picture at right (from I. Joughin) is of a meltwater lake approximately 3km by 2km
and 10m deep.