Mapping subglacial Antarctica using satellite observations of the ice surface

The ice-covered landscape of subglacial Antarctica is a crucial basal boundary condition for understanding the continental response to climate forcing, but is the least well mapped land surface in the inner solar system. Most current maps of the topography depend upon interpolation between non-uniform geophysical surveys, leading to significant spatial biases which are only gradually reduced by increasing survey coverage. We explore a different pathway to mapping subglacial Antarctica, utilising high-resolution satellite surveys of the ice surface and the principle that stress changes caused by flow over obstacles in the bedrock lead to ice-surface topography. By inverting ice-surface topography and combining the results with existing geophysical survey data, we produce a new elevation map of the subglacial landscape of interior Antarctica. As the ice-surface observations are spatially uniform, the insights provided by the new map into subglacial properties such as roughness can be compared on a continental scale, including in previously unsurveyed regions. In addition to this, the new map significantly improves our understanding of mesoscale (2-30 km) Antarctica sub-ice landforms, particularly subglacial mountain ranges and basins. It will therefore provide an improved boundary condition for ice-sheet models, alongside insights into geomorphological history, and guidance for future geophysical surveying.