Motion of the Dålk Glacier (Prydz Bay, East Antarctica): Application of unmanned aerial survey

Glaciers fluctuations are an indicator of changes in natural circulation mechanisms in the ‘glaciation–ocean–atmosphere’ system of the Southern Hemisphere. To assess the dynamics of the movement of shelf and outlet Antarctic glaciers, remote sensing methods are mainly used including unmanned aerial surveys. This article discusses methods for assessing the movement of the Dålk Glacier (Ingrid Christensen Coast, East Antarctica) using digital surface models (DSMs) and orthomosaics derived from data of multi-temporal unmanned aerial surveys. We estimated the dynamics of the Dålk Glacier over three weeks in January–February 2017 and over two years from January 2017 to January 2019. To study short-term displacements, a pseudo-parallax method was applied. Biennial displacements of the glacier were estimated by a visual comparison of orthomosaics. During three weeks of the 2017 austral summer, the average velocity of the actively moving part of the glacier was 1.3 m/day. At the same time, the average displacement of the central part of the Dålk Glacier was 423 m over two years, that is, the average velocity was about 0.6 m/day. Our results can serve as a basis for glaciological studies, monitoring, and prediction of fluctuations in hard-to-reach areas of outlet glaciers in Antarctica.