U-DEM: High spatiotemporal resolution surface elevations of the Canadian Arctic

Monitoring glacier surface elevation - and thus thickness - changes at high spatiotemporal resolution is essential for improving projections of future mass loss, constraining ice-flow models, and understanding the processes driving observed variability. Here, we present U-DEM, a new ice surface elevation dataset for the Canadian Arctic at 100 m spatial and 3-monthly temporal resolution, spanning the period from the launch of Sentinel-1 in 2014 through 2024. The dataset is generated using a deep-learning framework that combines CryoSat-2 swath altimetry, Sentinel-1 SAR imagery, and ArcticDEM stereo-derived elevation strips to produce a continuous, high-resolution record of surface elevation change.

First results demonstrate that the approach successfully captures spatial and temporal variability in glacier surface elevations that is not resolved by CryoSat-2 alone. The resulting DEMs show a substantially lower root-mean-squared-error than CryoSat-2, while reproducing small-scale topographic features such as narrow outlet glaciers and complex marginal zones. These improvements are particularly important in regions characterized by steep gradients and dynamic glacier behaviour.

By providing a consistent, high-resolution elevation time series across the Canadian Arctic, U-DEM opens new possibilities for a wide range of glaciological applications. These include transient modelling of glacier evolution, inverse modelling to constrain bedrock topography, particularly in regions affected by surging glaciers, and investigations of seasonal variability and the processes driving surface elevation changes. Beyond the Canadian Arctic, the U-DEM framework is designed to be transferable and can, in principle, be applied to any region of interest where Sentinel-1 and CryoSat-2 data are available.