Margin Migration of Siple Dome Ice Streams

In this modeling project, we attempted to explain the large velocity gradients
observed across the margins of Whillans Ice Stream. Using measured topography
and ice temperatures, we concluded that large enhancement factors, presumably
due to ice fabric re-orientation, were needed to explain the surface velocity
gradients. This result was presented at WAIS 2001. In further work, we then
found that an appropriate treatment of continuum damage mechanics (Pralong et
al., 2003) can also lead to weakening of ice at the margins (Luthi et al, WAIS
2001).

To compare Whillans Ice Stream to other ice streams we compared its flow to
that of Jakobshavn Isbrae (Truffer and Echelmeyer, 2003). This work highlighted
the differences between shallow and flat ice streams on very weak beds and
steeper outlet glaciers flowing through deep troughs. Further modeling work led
to the development of a fully 3D ice flow model.

Pralong, A., M. Funk, and M.P. Luthi. 2003. A description of crevasse formation
using continuum damage mechanics. Ann. Glac., 37, 77-82.

Truffer, M. and K.A. Echelmeyer. 2003. Of icestreams and isbrae. Ann. Glac.
36, 67-72.