Topography reconstruction and evolution analysis of outlet glacier using data from unmanned aerial vehicles in Antarctica

Abstract

Reconstruction of glacial topography is important for assessing the ice dynamics of glaciers in the past and understanding how they may respond to climate change in the future. As an emerging strategy, unmanned aerial vehicles (UAVs) have been successfully used in glaciology applications to reconstruct surface topography and monitor the short-term dynamics of glaciers. However, none of these studies have focused on the ice dynamics of outlet glaciers in Antarctica. In this study, based on a combination of UAVs and a base station, we investigated Dalk Glacier, a typical marine-terminating glacier in East Antarctica, during two Chinese National Antarctic Research Expeditions from 2019 to 2020. By applying structure-from-motion and multi-view-stereo photogrammetry, high-resolution orthomosaics and digital elevation models of the glacial topography were reconstructed with centimeter-level accuracy via in situ validation, thus marking the first application of UAV observations in the monitoring of Antarctic outlet glaciers. Topographic evolution of the glacier was quantitatively analyzed from various aspects including ice velocity, surface elevation, crevasses, and ice front calving. A maximum ice velocity of ∼ 310 m a-1 at its terminus was observed, which was ∼ 90 m a-1 greater than that in satellite-based studies. We analyzed in detail the spatially heterogeneous changes in the ice velocity and surface elevation of the glacier under the influence of an ice rumple at its calving terminus. Combined with satellite images and existing datasets, we hypothesize that the large ice rumples at the glacier terminus could deform the glacier and potentially damage its structural integrity, thereby limiting the growth of its terminus.

Keywords

• Unmanned aerial vehicle
• Structure-from-motion and multi-view-stereo
• Dalk Glacier
• East Antarctica
• Ice rumple