Mass balance of IGAN Glacier (the Polar Urals) in 2018–2023

The results of observations of the mass balance of the IGAN glacier by the geodetic method using DGPS surveys and constructed multi-temporal digital models of the glacier surface (DEM) for the period 2018–2023 are presented. Comparison with data from previous years (1963, 2008, 2018) obtained using a similar methodology allowed to assess changes in glacier mass over the entire observation period and its features over the short span of the last five years. It was found that the glacier continues to shrink. In 2023, the area of its northern part was 0.43±0.04 km², having decreased by 38% compared to 1963. From 2018 to 2023, the glacier surface dropped by an average of 3.73 m. During this period, the glacier lost 1.593 × 10⁶ m³ of ice. The average annual specific mass balance was negative –627±45 mm w.e. This value is almost twice as high as in the period 2008–2018, when it was –372±63 mm w.e. The cumulative mass balance over five years reached –3134±224 mm w.e. The main cause that determines the glacier shrinkage throughout the entire observation period from 1963 to 2023 is the increase in summer air temperatures occurring on the background of practically unchanged winter precipitation. Along with this, it was found that the glacier lost less over the entire observation period (2018–2023) than in the last three balance years (2020-2023). A possible explanation for this could be the positive mass balance in 2019, in which the DGPS survey could not be conducted. To confirm this assumption, data from meteorological observations of air temperature, precipitation, snow measurement and monitoring of the snow line from satellite images at the end of the ablation period were used. Based on the analysis of these data, a conclusion was made that such a situation was possible due to the anomalous winter precipitation and cold summer in that specific year.