The Golubina Glacier is of the valley type and is located on the northern slope of the Kyrgyz Ala-Too range, in the basin of the Ala-Archa River (a left tributary of the Chu River). With an area of 6.2 km², its length exceeds 5 km. The highest point of the glacier basin is at an altitude of 4220 m, and the firn line is at an altitude of 3860 m. The firn basin of the glacier is a vast hollow, approximately 3 km in diameter, surrounded by snow-covered rocks. At the exit from the firn basin, the glacier forms an extensive icefall zone, where the height difference reaches 100-150 m. The tongue of the glacier, 0.5 km wide, ends with a steep slope at an altitude of 3400 m. Along the glacier tongue, there are ridges of lateral moraines, and there are few moraine deposits on the surface of the glacier.
Data from the Central Asian Institute of Applied Geosciences indicate a significant reduction in the area of the Golubina Glacier in the Ala-Archa Gorge from 1861 to 2015; for instance, from 1917 to 1961, the Golubina Glacier retreated by almost 1 km. In recent years, the Golubina Glacier has retreated another 200 meters.
Glaciers are an important source of fresh water in Central Asia, as maximum glacial runoff occurs in the summer months when precipitation is minimal and water demand is at its peak. Many studies have focused on the changes in the area of the Tien Shan glaciers; however, to assess river runoff and the impact of climate change, data on changes in ice mass are necessary. Despite the importance of such studies, similar work has only been completed for a small number of glaciers. Mass balance estimates using geodetic methods can complement and extend existing series of direct measurements on glaciers. This study assessed changes in the area and mass of glaciers located in the Ala-Archa valley in the Kyrgyz Tien Shan using stereo images from the Corona satellite from 1964 and 1971, ASTER stereo images from 2012, the SRTM digital elevation model, and other optical data, including LANDSAT ETM+ and RapidEye. Additionally, modeling of ice thickness was performed based on shear stress at the bedrock and the surface topography of the glaciers. The results showed that from 1964 to 2010, the glaciers continuously shrank and lost 18.3±5.0% of their total area. The average mass balance was −0.45±0.27 m w.e. per year for the period from 1964 to 1999 and −0.42±0.66 m w.e. per year from 1999 to 2012. For the Golubina Glacier, a slight mass accumulation was recorded from 1964 to 1971, and a slowdown in mass loss was observed from 1999 to 2012. These results are consistent with existing data from direct mass balance measurements conducted from 1962 to 1994 and from 2010 onwards. As of 2000, the total volume of ice was 1.56±0.47 km³. Thus, if the mass of ice continues to decrease at the same rate, the glaciers in the study area will completely melt by 2100.
