An iterative inverse method to estimate basal topography and initialize ice flow models

Published: Nov 1, 2013 by The PISM Authors

A new inverse approach to reconstruct distributed bedrock topography and simultaneously initialize an ice flow model is proposed. The procedure runs PISM multiple times over a prescribed period, while being forced with space- and time-dependent climate input. After each iteration bed heights are adjusted using information of the remaining misfit between observed and modeled surface topography. Synthetic experiments with constant-climate forcing demonstrate convergence and robustness of the approach. Application to Nordenskiöldbreen, Svalbard, forced with height- and time-dependent climate input since 1300 AD show a high correlation against radar-observed thicknesses. Remaining uncertainties can be ascribed to inaccurate model physics, in particular, uncertainty in the description of sliding.