ИСТИНА

In 1999 and 2010-2013 ground-based radio-echo sounding measurements were performed on 15 glaciers of Nordenskiöld Land in Svalbard. This data together with total thickness and volume of glaciers published earlier in 2013 and 2016, were used to estimate the distribution of thickness and volume of cold and temperate ice. Strong scattering of radio waves on water inclusions in temperate ice and strong extended radar reflections from internal reflecting horizon (IRH) correspond to cold-temperate transition ice surface (CTS), where ice temperature reaches 0°C, were used to identify 12 glaciers as polythermal ones with upper cold ice layer and lower temperate ice layer at pressuremelting point. For 11 of polythermal glaciers delay time from IRH was used to calculate thickness and volume of cold ice. Correct estimation of CTS depth were performed using difference in power reflection form IRH and bed. Thickness and volume of temperate ice were calculated as difference between total and cold ice thickness and volume. Remaining 3 glaciers were identified as cold type glaciers due to lack of internal reflections except of buried crevasses and glacial moulines. Also sites of meltwater input into glaciers temperate core and bed were revealed.