ИСТИНА

The Vavilov ice cap (79.30° N, 95.47° E) is situated on October Revolution Island of the Severnaya Zemlya archipelago. In this project the images obtained from Landsat-1, 5, 7, 8, Terra (ASTER), Sentinel-1 and Corona were applied. We found out that from 1963 to 2017 the ice cap margin advanced seaward by 11.7 km (central line), and its area increased by 133 km2. The accelerated advance started in 2010, in summer 2016 the marginal front terminated in sea began to disintegrate, in 2017 the advance continued but with lower velocity. The data on ice cap velocities was taken from two sources. The first one is GoLIVE project, also we analysed the synthetic aperture radar data from Sentinel-1 satellite. Comparison of the velocities acquired from two sources for the same period shows that they are in a very good correlation. Maximum velocity of glacier was in 2016 and reached 25.4 m/day. From 2016 the velocity started to decrease. To evaluate the volume changes of western part of the Vavilov ice cap we analysed ASTER DEMs of 2000 and 2015, radar data obtained during fieldwork in 2014 and topographic maps of scale 1:200 000. Above the contour line of 100 m (2015) the main trunk of the newly formed outlet glacier thinned by at least 1.918 km3, and at the same time its snout increased by 4.101 km3. Acknowledgments. This study is supported by the RNF grant 14-37-00038, RFBR-BRICS grant 17-55-80107, RFBR grant 14-37-00038, and the State assignment 01201352474.