Decennial Geomorphic Transport From Archived Time Series Digital Elevation Models: A cookbook for tropical and alpine environments

On the seasonal timescale, for accessible locations and when manpower is available, direct observations and field surveys are the most useful and standard approaches. However very limited studies have been conducted through direct examination on decennial-to-century timescales due to observational constrains. Here, we present an open and reproducible pipeline based on historical aerial images (across a timeline of up to 70 years) that includes sensor calibration, dense matching, and elevation reconstruction in two areas of interest that represent pristine examples of tropical and alpine environments. The Remparts and Langevin rivers, on Réunion Island, and the Bossons glacier, in the French Alps, share limited accessibility (in time and space) that can be overcome only by remote sensing. We reach a metric-to-submetric resolution close to the nominal image spatial sampling. This provides elevation time series with better resolution than most recent satellite images, such as Pleiades, in a decennial time period.