Historical aerial imagery–derived Digital Elevation Models and orthomosaics for glacier change assessment in the western Antarctic Peninsula since 1989

The Antarctic Peninsula (AP) is a hotspot of global warming, with pronounced atmospheric warming reported during the 20th century. Although it is critical in terms of climate change studies, the mass balance of glaciers prior to 2000 remains poorly constrained. Existing mass balance estimates are further characterized by high uncertainties due to a lack of observations. In contrast, more than 30000 historical images in archives are the sole direct observations to quantify past glacial changes and their contribution to sea-level rise. 

In this study, we present a unique, timestamped, high-resolution Digital Elevation Model (DEM) and orthomosaic dataset, derived from aerial imagery that covers about 12000 km2 area on the western Antarctic Peninsula and surrounding islands between 66–68° S. We used a film-based aerial image archive from 1989 acquired by the Institut für Angewandte Geodäsie (IfAG), and is kept in the Archive for German Polar Research at the Alfred Wegener Institute, Germany, to generate the historical DEMs and orthoimages. The historical DEMs were co-registered to the Reference Elevation Model of Antarctica (REMA) mosaic on stable terrain. Our historical DEMs have vertical accuracies better than 6 m and 8 m with respect to modern elevation data, REMA, and ICESat-2, respectively. We have made this dataset publicly available at  https://doi.org/10.5281/zenodo.16836526.

Initial mass balance estimates from DEM differencing of our 1989 DEM with recent surfaces from REMA strip DEMs show a near-constant ice mass despite widespread glacier frontal retreat and thinning. We hypothesize that low-elevation ice thickness loss in this period is largely compensated by higher surface mass balance in higher areas. However, this regime appears to be changing, with glaciers transitioning toward increased dynamic activity with enhanced mass loss, and higher ice fluxes.