Abstract: Abstract
The grounding line is a key element acting on the dynamics of coastal outlet glaciers.
Knowing its position accurately is fundamental for both modelling the glacier dynamics
and establishing a benchmark to which one can later refer in case of change. Here we
� �map the grounding line of the Astrolabe Glacier in East Antarctica (66 41 S; 140 05 E),
using hydrostatic and tidal methods. The first method is based on new surface and
ice thickness data from which the line of buoyant flotation is found. We compare this
hydrostatic map with kinematic GPS measurements of the tidal response of the ice
surface. By detecting the transitions where the ice starts to move vertically in response
to the tidal forcing we find control points for the grounding line position along GPS
profiles. With the help of a 2-dimensional elastic plate model, rigid elastic deviations are
computed and applied to these control points. Once the extent of the grounding zone,
the kinematic approach is consistent with the hydrostatic map. These two approaches
lead us to propose a grounding line for the Astrolabe Glacier that significantly deviates
from those obtained so far from satellite imagery.