Optimising detection of Greenland's active subglacial lakes with DEMs: evaluating coregistration and detrending strategies

The GLOBE (Greenland Subglacial Lake Observatory) project aims to create a comprehensive inventory of Greenland's active subglacial lakes through systematic analysis of high-resolution Digital Elevation Models (DEMs) combined with satellite altimetry data. In particular, the complete 2-meter resolution ArcticDEM database covering the entire ice sheet between 2008 and 2025 is utilised for this purpose. Since initial proof-of-concept studies demonstrated the viability of detecting subglacial lake dynamics using elevation variance, substantial progress has been made in extending this approach across larger spatial scales and more diverse glaciological conditions.

In this work, we present methodological refinements necessary for robust, systematic detection of subglacial lake signatures at the ice-sheet scale. We evaluate the impact of different coregistration methods (including no coregistration) on the reliability of the standard deviation of elevation maps used for lake identification. Additionally, we assess the effectiveness of detrending long-term ice-sheet elevation changes to isolate the shorter-term, localised elevation variations associated with subglacial lake drainage and filling events. As the project scales to cover all the ice sheet, understanding how these processing choices affect detection accuracy, precision, and the separation of signal from noise is critical for ensuring robust, reproducible results.

Preliminary results presented here offer insights into the relative importance of the different parameters and steps involved in the GLOBE pipeline and their contribution to lake identification. We demonstrate how these results inform best practices for systematic subglacial lake mapping across Greenland and the subsequent integration of subglacial hydrology into larger-scale ice sheet models, thereby improving predictions of ice sheet stability and mass loss.