Dynamics and mass balance of the ice-sheet/ice-shelf regime at Nivlisen, Antarctica, as derived from a coupled three-dimensional numerical flow model

Abstract

AbstractThe aim of this study is to derive basic ice dynamics for Nivlisen, a relatively small ice shelf in Dronning Maud Land, East Antarctica, and its drainage area. Therefore, the adaptation of an existing three-dimensional numerical flow model (Sandhäger, 2000) was undertaken, which had been applied previously to Ekstromisen and its drainage system. Compared to that region, Nivlisen and its drainage area represent a significantly more complicated geometrical situation. This has consequently large impacts on the flow regime, i.e. several modifications are necessary and reasonable. The diagnostic modelling is carried out in order to derive the current ice dynamics. The resulting ice-flow velocities seem to be too small compared to typical values for such glaciers. Therefore, the basal temperature at some gridpoints was set to pressure-melting point to obtain more realistic results. Furthermore, the use of a spatially varying parameter to describe basal sliding is advisable. Presenting the numerical results, the focus lies on the modelled ice-velocity field. The mass-balance quantities are calculated from the simulated velocity distribution and the underlying ice-geometry models derived from different datasets. The diagnostic results will serve as the basis for future prognostic modelling studies.