Published on 23 February 2019
Glaciers in the Caucasus have been continuously shrinking during the 20th and in the beginning of the 21st century. Mountain glaciers provide up to 70% of the total river runoff in the adjacent territories. Realistic prediction of future glacial run-off is a key problem of water supply in mountain and piedmont regions. The task of prediction can be solved by means of dynamical modeling of mountain glaciers. Because of lack of regular observations, it is feasible to focus on several reference glaciers in the region and to further extrapolate modeling results on the whole glaciated area. In the paper, we report about application of a 3D higherorder ice flow model coupled to a surface mass-balance model for carrying out prognostic numerical experiments aimed at simulation of future dynamics of Djankuat Glacier. Djankuat is a typical valley glacier on the northern slope of the main Caucasus chain. It is one of the most studied glaciers in Russia, which has been continuously monitored during the last fifty years. From the point of view of completeness and duration of observations, Djankuat is an ideal glacier for mathematical modeling. Considerable parts of the ablation zone of Djankuat are covered with debris. Heat and physical properties of the debris layer are very different from those of ice. Debris layer determines ablation rate and run-off regime. Dependently on thickness, it can accelerate ablation or totally isolate ice cover from melting. To force the model, we utilized observations from the nearest weather stations (Terskol and Mestia), as well as accumulation and ablation field measurements as controls. In the prognostic numerical experiments, we simulated possible Djankuat evolution until the year 2100 under stationary climatic conditions. We established that geometry of the glacier in imbalance with the climatic conditions of the decade 1999–2008 years. To reach the equilibrium, the glacier will need nearly half a century taking into account insulating role of the debris partially covering ablation zone. In case debris cover is not considered, the glacier does not reach equilibrium until the end of the current century. Supraglacial moraine is responsible for 20–65% reduction of the annual melting under the debris layer dependently on its thickness. For the whole glacier, with the debris cover taken into account, the annual amount of melt water reduces by 9-10% when the glacier equilibrates with climate.
Categories: Articles, Geo-ecological,-Recreational-and-Biomedical-Issues-of-SDMT
Tags: mathematical model, горный ледник, баланс массы, моренный чехол, ледниковый сток
ISSN 1998-4502 (Print) ISSN 2499-975Х (Online)