EGU22-4904
https://doi.org/10.5194/egusphere-egu22-4904
EGU General Assembly 2022
© Author(s) 2022. This work is distributed under
the Creative Commons Attribution 4.0 License.

The effects of rheological parameters on ice-shelf flow on centennial time scales.

Olga Sergienko
Olga Sergienko
  • GFDL/Princeton University, Princeton, United States of America (osergien@princeton.edu)

On timescales longer than several months, ice flow is treated as a non-Newtonian fluid, which viscosity depends on the second invariant of the strain-rate tensor and the temperature-dependent ice-stiffness parameter. This power-law dependence is known as Glen's flow law. Although results of laboratory experiments and inferences from in situ observations suggest a range of the power-law exponent n  from 1 to 5, the value of 3 is widely used. In studies focused on ice-shelf dynamics, the traditional approach is to use remote-sensing observations to infer the ice-stiffness parameter by means of inverse methods assuming a constant value of n=3. Focusing on the floating tongue of Pine Island Glacier, the inversions of the ice-stiffness parameter are performed for various constant as well as spatially variable values of n using present-day observations. Using the inferred parameters and basal melting derived from remote-sensing observations, the Pine Island Glacier Ice Shelf flow is simulated for hundred years. Results of simulations indicate that the effects of rheological parameters are of the order of 5%. The difference between results of hundred years simulations with observationally derived  and spatially uniform basal melting are of the order of 40%. These results indicate that on centennial timescales the ice-shelf flow is more sensitive to details of basal melting than to rheological parameters, provided the latter are constrained by observations.

How to cite: Sergienko, O.: The effects of rheological parameters on ice-shelf flow on centennial time scales., EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-4904, https://doi.org/10.5194/egusphere-egu22-4904, 2022.