Supra-glacial debris cover changes in the Greater Caucasus from 1986 to 2014
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Knowledge of supra-glacial debris cover and its changes remain incomplete in the Greater Caucasus, in spite of recent glacier studies. Here we present data of supra-glacial debris cover for 659 glaciers across the Greater Caucasus based on Landsat and SPOT images from the years 1986, 2000 and 2014. We combined semi-automated methods for mapping the clean ice with manual digitization of debris-covered glacier parts and calculated supra-glacial debris-covered area as the residual between these two maps. The accuracy of the results was assessed by using high-resolution Google Earth imagery and GPS data for selected glaciers. From 1986 to 2014, the total glacier area decreased from 691.5±29.0 to 590.0±25.8 km2 (15.8±4.1 %, or ∼0.52 % yr−1), while the clean-ice area reduced from 643.2±25.9 to 511.0±20.9 km2 (20.1±4.0 %, or ∼0.73 % yr−1). In contrast supra-glacial debris cover increased from 7.0±6.4 %, or 48.3±3.1 km2, in 1986 to 13.4±6.2 % (∼0.22 % yr−1), or 79.0±4.9 km2, in 2014. Debris-free glaciers exhibited higher area and length reductions than debris-covered glaciers. The distribution of the supra-glacial debris cover differs between the northern and southern and between the western, central and eastern Greater Caucasus. The observed increase in supra-glacial debris cover is significantly stronger on the northern slopes. Overall, we have observed up-glacier average migration of supra-glacial debris cover from about 3015 to 3130 m a.s.l. (metres above sea level) during the investigated period.
Tielidze , L G , Bolch , T , Wheate , R D , Kutuzov , S S , Lavrentiev , I I & Zemp , M 2020 , ' Supra-glacial debris cover changes in the Greater Caucasus from 1986 to 2014 ' , The Cryosphere , vol. 14 , no. 2 , pp. 585-598 . https://doi.org/10.5194/tc-14-585-2020
Copyright © Author(s) 2020. This work is distributed under the Creative Commons Attribution 4.0 License.
DescriptionThis work was supported by Shota Rustaveli National Science Foundation of Georgia (SRNSFG; grant no. YS17_12).
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