Estimation of Spatial Distribution of Debris Cover on Caucasus Glaciers Using ASTER Imagery

Abstract

 It is important to estimate medium-to long-term melting rate of mountain glaciers, which significantly affect global sea-level rise and changes in water resources. Debris cover on glacier is widely present in glacier ablation area and its spatial distribution greatly affects glacier melt rates. However, it is difficult to estimate the spatial distribution of debris thickness at large scale only from field measurements. In this study, we attempted to estimate the spatial distribution of debris cover of the whole Caucasus region using satellite data. A comparison of our results and field measurements by previous studies indicated that the debris cover more than 5cm in thickness can be estimated reasonably. Also, we found that the degree-day factor of about 20% of glaciers in Caucasus region becomes around half relative to that of debris-free surface condition, due to the insulating effect of debris cover. Our results highlight the importance of debris cover and its spatial distribution for understanding glacier mass change in this region.