Detecting Altimetric Changes in Arctic Landscapes Using Historical Aerial Imagery-Derived Digital Elevation Models (hDEMs): Case Study of the Black Mountain Alluvial Fan Complex, Canada

In the rapidly changing Arctic, reconstructing landscapes over the last 50 years is essential to understanding effects due to climate-induced geomorphic change. While region-wide warming became measurable in the 1980s, spatially extensive high-latitude elevation data sets extend temporally back to the 2000s. Historical aerial imagery archives provide data sets of high-resolution imagery from the mid-to late 1900s with stereo-capability that can be harnessed to create historical digital elevation models (hDEMs). Reconstructing a surface from the past is challenging due to a lack of ground control from that era to constrain it in space, especially at high latitudes. The main purpose of this study was to determine whether an hDEM could be used to detect altimetric change in an area of poor ground control. We developed an hDEM from historical aerial imagery over the Black Mountain alluvial fan complex in the Northwest Territories, Canada, and used satellite imagery-derived ground control points to constrain the model in space. The resulting hDEM, when compared with the ArcticDEM, yields a vertical root mean square error of 5.19 m. We were able to isolate approximately 30 to 40 m of altimetric change from a landslide (circa 2013 to 2016) in the Black Mountain Fan catchment, supporting the supervised use of hDEMs for change detection studies. Data produced from this study are available on Dryad (doi:10.5061/dryad.mw6m90691).