GlaRe, a GIS tool to reconstruct the 3D surface of palaeoglaciers

• GlaRe is a tool for palaeoglacier 3D surface reconstruction from bed topography.
• GlaRe is coded in Python and runs in ArcGIS as a toolbox.
• The theory of perfect plasticity equilibrium glacier profile is considered.
• Interpolation methods for glacier 3D surface creation are described and discussed.
• GlaRe is tested with two extant glaciers, showing a small, acceptable error.

Glacier reconstructions are widely used in palaeoclimatic studies and this paper presents a new semi-automated method for generating glacier reconstructions: GlaRe, is a toolbox coded in Python and operating in ArcGIS. This toolbox provides tools to generate the ice thickness from the bed topography along a palaeoglacier flowline applying the standard flow law for ice, and generates the 3D surface of the palaeoglacier using multiple interpolation methods. The toolbox performance has been evaluated using two extant glaciers, an icefield and a cirque/valley glacier from which the subglacial topography is known, using the basic reconstruction routine in GlaRe. Results in terms of ice surface, ice extent and equilibrium line altitude show excellent agreement that confirms the robustness of this procedure in the reconstruction of palaeoglaciers from glacial landforms such as frontal moraines.