Detection of crevasses by geomorphometric treatment of data from unmanned aerial surveys

For Antarctic research, one of the important support tasks is a monitoring of sledge routes and other visited areas for detection of open crevasses and revealing of hidden, snow-covered ones. We study the possibility of revealing hidden crevasses with geomorphometric treatment of high-resolution, glacier digital elevation models (DEMs) produced from imagery captured by unmanned aerial systems (UASs). The study was conducted in East Antarctica, at a sledge route from the Progress to Vostok Stations. The survey performed with Geoscan 201 Geodesy UAS, resulted in a set of aerial images with a resolution of 6 cm. From these images, we produced glacier DEMs for a typical area with snow-covered crevasses. The glacier DEMs with the resolutions of 25 cm, 50 cm, and 1 m were treated by geomorphometric methods. We derived models of 16 morphometric variables including horizontal and vertical curvatures. For the 1-m gridded DEM, mapping of some variables allowed us to reveal one of the crevasses. The approach is functional, at least, for revealing crevasses with a width of 1.5 m and wider, covered by the snow layer with a thickness of up to 1.2 m.