Map analysis techniques for glaciological applications

This paper presents map analysis of digital elevation models for glaciologi cal applications. The approach has been to combine spatial information desc ribing the geometry of the glaciers with physical models of glaciological p rocesses and to adjust empirical parameters to give a best fit with field o bservations. This applies to description of the basal shear stress and the resulting flow due to deformation of the ice. The outputs display spatial d istributions, which can be adjusted to field observations through flexible routines of averaging the geographical information. Further, this approach is applied to description of the potential driving water along the bed, def ined by the basal topography of the glacier and a model assuming that the b asal water pressure is related to the thickness of the ice. The results pro duce predictions of the location of subglacial waterways and their drainage basins, which can be adjusted to field observations by choice of an empiri cal parameter, giving the basal water pressure as a fraction of the ice ove rburden pressure. A routine is presented that integrates the meltwater cont ribution downglacier to the various river outlets, given the glacier surfac e ablation.