popovnin_2005.htm

Bulletin of Glaciological Research 22 (2005) 121-133
©Japanese Society of Snow and Ice

A 34-year-long record of mass balance and geometric changes of the Djankuat
Glacier, Caucasus

Victor V.Popovnin¹ and Renji Naruse²
1 Cryolithology & Glaciology Dept, Geographical Faculty, Moscow State University, Leninskiye Gory, Moscow, 119992, Russia
2 Institute of Low Temperature Science, Hokkaido University, Sapporo, 060-0819 Japan
 

Abstract

　Dynamics of mass balance and its components of the Djankuat Glacier, representative for the Central Caucasus, during the 34-year-long period of direct measurements are analyzed. Mean mass balance is slightly negative (-160mm w.e.), with average accumulation and ablation values coming to 2410 and -2570mm w.e., correspondingly. As a result, orthogonal projection of the Djankuat Glacier area on the northern macro-slope of the Main Caucasus Ridge decreased by 12% in the period 1968-1999, while its surface lowered slightly less than 6m (in water equivalent). Variability of both mass balance components is practically the same at the Djankuat Glacier. Mass balance extremes coincide with the years of maxima of its components. The whole 34-year-long observation period is marked by weak trends towards increase of both balance constituents. Dominant tendency towards the improvement of the Djankuat Glacier budget conditions changed to the contrary (or, at least, was interrupted) since 1998. It is not clear whether this pattern indicates the beginning of the new stage of glacier degradation in the Caucasus or it should be regarded only as a natural fluctuation of atmospheric processes.