The pre-industrial digital elevation model of the Greenland Ice Sheet from the 17th and 18th Centuries

A large uncertainty surrounding the current state of the Greenland Ice Sheet (GIS) and the predictions for future sea-level change stem from a lack of knowledge in the historical boundary and shape of the ice sheet. Prior to the 1970s, the ice sheet is reliant on aerial imagery and digital photographs. To help improve ice sheet model projections, in particular for the Ice Sheet Model Intercomparison Project for CMIP6 (ISMIP6) group, the focus is to provide a historical perspective of the boundaries and thickness. The digital elevation model is built using trim lines, geomorphic mapping, known points of boundary conditions, early explorer records, through a combination of biogeographical, archaeological and geologic records to amalgamate into a historical DEM. As more numerical simulations are based on the same DEM input yet the response time of the ice sheet is slow enough where a pre-industrial DEM would provide insight into the climate-ice sheet interactions of the recent past. Furthermore, this work will provide an observation-based estimate of change to the GIS and has the potential to lead to a calculation of the spatial ice mass loss from previous centuries. This DEM will increase understanding of the spatial extent of the GIS prior to the 20th century which remains crucial for evaluating the reliability of numerical simulations to predict global sea-level rise.