The thermomechanics of ice-stream margins
Jenny Sukale1,2 and James R. Rice1
Maps of the surface velocity of ice in West Antarctica show that
flow localizes in narrow bands of fast flowing ice streams bordered by ridges
of nearly stagnant ice. Despite the importance of ice streams for the stability
of the West-Antarctic Ice Sheet, our understanding of the physical processes
that determine their flow speed and width is incomplete. Here, we study the
thermal and mechanical properties of ice-stream margins, where flow transitions
from rapid to stagnant over a few kilometers. Our goal is to explore under
which conditions the intense shear deformation in active ice-stream margins may
lead to deformation-induced melting. We propose a 2D model that represents a
cross-section through the ice-stream margin perpendicular to the downstream flow direction.
We include advection, latent heat and surface crevassing into our model and
strive for a realistic description of the ice rheology. Our simulations suggest
that a zone of temperate ice is likely to form in active shear margins.
1Harvard University; 2Stanford
University