Empirical correction of systematic orthorectification error in Sentinel-2 velocity fields for Greenlandic outlet glaciers

Abstract. By utilising imagery from overlapping orbits, the Sentinel-2 programme offers high-frequency observations of high-latitude environments well in excess its 5 d repeat rate, which is valuable for obtaining large-scale records rapid environmental change. However, production glacier velocity datasets optical feature tracking limited by orthorectification error ESA products, introduces significant systematic errors (on order tens metres) into displacement fields produced cross-track image pairs. As a result, most standard processing chains ignore pairs, limits opportunity to fully benefit Sentinel-2's during periods intermittent coverage or dynamic events. Here, we use temporally complete empirically reconstruct error, allowing corrected be four key fast-flowing marine-terminating outlets across Greenland Ice Sheet between 2017–2021. We show that data agree with comparison derived (Landsat 8) and synthetic aperture radar (Sentinel-1) data. The density available pairs produces noisier dataset than these comparative records, but best-fit reconstructed time-series modelling can identify change (e.g. summer slowdowns), even where gaps exist other datasets. empirical maps commercial DEM used orthorectify scenes over 2017–2021 likely shares sources freely public DEMs, opening avenues analytical correction future.