a
b
c
d
DFig. 20. Contours of Glacier No. 200: a − according to the topographic map, b − according to the Landsat 7 ETM+ sensor image of August 31, 2010, c − according to the Landsat 8 OLI TIRS sensor image of September 5, 2015, d − according to the Landsat 8 OLI TIRS sensor image of September 11, 2020.
