Modelling glaciers’ melting in Central Caucasus (the Djankuat and Bashkara Glacier case study)

The A-melt model was applied to assess the contribution snow and ice melting to river flow during the summer period of 2017 for the Bashkara and Djankuat glaciers located in the Caucasus. During the study period, the Djankuat river runoff amounted to 120 thousand m3, while the peak value of snow and ice melting was 300-400 thousand m3 per day, and on average 189 thousand m3. The significant influence of groundwater on the river flow is traced. The melt water contribution to the glacial lake Bashkara outburst manifested in the gradual accumulation of water large volumes over the summer period. The melting of snow and ice the day before the lake outburst reached 31 thousand m3, with an average value of 192 thousand m3 for the Bashkara basin. The total melting volume of the Djankuat basin was 0.016 km3, and of the Bashkara basin – 0.017 km3. As a result, the A-Melt model demonstrates the evaluation ability of glaciers’ impact on mountain rivers runoff

Hydrological, meteorological observations and isotopes sampling results during 2019-2020 at Djankuat Glacier Station in the North Caucasus, Russia

This is an update of a dataset on the long-term complex glaciological, hydrological, meteorological observations and isotopes sampling in an extremely underreported alpine zone of the North Caucasus. The Djankuat research basin is of 9.1 km2, situated on elevations between 2500 – 4000 m, by 30% covered with glaciers. The biggest in the basin Djankuat glacier was chosen as representative of the central North Caucasus during the International Hydrological Decade and is one of 30 'reference' glaciers in the world that have annual mass-balance series longer than 50 years (Zemp et al, 2009). The original dataset covers 2007-2017, this update - 2019-2020. In total, the dataset contains the result of yearly measurements of snow thickness and density; dynamics of snow and ice melting; measurements of water runoff, conductivity, turbidity, temperature, δ18O, δ2H on the main gauging station with a one-hour or several-hours step depending on the parameter; data on δ18O and δ2H sampling of liquid precipitation, snow, ice, firn, groundwater in different parts of the watershed regularly in time during the melting season; precipitation amount, air temperature, relative humidity, shortwave incoming and reflected radiation, longwave downward and upward radiation, atmospheric pressure, wind speed and direction – measured on several automatic weather stations within the basin with 15 min – one-hour step; gradient meteorological measurements to estimate turbulent fluxes of heat and moisture, measuring three components of wind speed at a frequency of 10 hertz to estimate the turbulent impulse heat fluxes over the glacier surface by the eddy covariance method. The observations were held during ablation period June-October and were interrupted in winter. The dataset will be further updated. The dataset can be useful for developing and verifying hydrological, glaciological and meteorological models for high elevation territories, to study impact of climate change on hydrology of mountain regions, using isotopic and hydrochemical approaches to study mountain territories