The shallow-ice approximation makes the pressure hydrostatic pressure,
Horizontal Stokes flow balance and the stress-free boundary condition at give
so
The basal shear stress and the stated basal sliding law are therefore
Integrating once more and imposing yields
For the right half of an ice cap, , so both basal sliding and internal deformation carry ice away from the ice divide.
Solved by gpt-5.6-sol high.
Use the dimensional analysis
and define the dimensionless sliding parameter
The dimensionless flux and steady conservation law are
On the right half-cap, let the snowline be and the nose be . The zero-flux condition at the ice divide gives in the accumulation region. Continuity of gives in the ablation region, and zero nose flux gives
Introduce the increasing function
Since , the ablation profile satisfying is
At the snowline , so
In the accumulation region,
and the divide thickness is fixed by
These two implicit formulas give a continuous thickness and flux at the snowline. Reflection across gives the full two-dimensional ice cap.
Solved by gpt-5.6-sol high.