Temporal Variability of Glacier Albedo in the Svalbard Archipelago: A Case Study of the Aldegonda Glacier

This study investigates the temporal variability of surface reflectance—albedo—of the Aldegonda Glacier (Nordenskiöld Land, West Spitsbergen Island) based on optical satellite imagery from 2016 to 2024. Understanding glacier albedo is crucial for assessing feedback mechanisms in the energy and mass balance systems of low-altitude glaciers in the Svalbard Archipelago.

To estimate surface albedo, Sentinel-2 Level-2A satellite images with a spatial resolution of 10–20 meters were used for August, when glacier ablation is most intense. Preprocessing included the calculation of integrated albedo using empirical methods that account for the spectral characteristics of the satellite channels and the optical properties of the atmosphere. As a result, spatially distributed albedo values were obtained across the entire glacier surface, with shaded areas excluded from further analysis.

The thickness of the ice melt layer for each season from 2016 to 2024 was measured using fourteen ablation stakes. Incoming solar radiation and air temperature data were taken from the microclimate observation archive at the Aldegonda Glacier, based on records from an automatic weather station.

The analysis revealed a trend of decreasing surface albedo of the Aldegonda Glacier from 2016 to 2024. Interannual variability in ablation was primarily explained by changes in air temperature and albedo. A positive linear correlation coefficient of 0.77 was found between ablation and air temperature. Albedo also proved to be a significant factor, with a correlation coefficient of −0.70, indicating that a increase ablation is associated with decreased in albedo. A positive correlation was also identified between ablation and shortwave radiation balance (correlation coefficient 0.76), highlighting the importance of surface reflectivity in melting processes.

Based on a regression analysis, a two-factor model was proposed for estimating glacier surface ablation as a function of albedo and mean August air temperature:

Ablation = 2.37 + 0.15 × Air Temperature – 3.52 × Albedo,

where 2.37 is the intercept, 0.15 is the coefficient for air temperature, and −3.52 is the coefficient for albedo. An important note is that ablation is assumed to be zero when the air temperature is zero or negative. This model explains 67.4% of the variance in ablation (R² = 0.67). The remaining 32.6% is likely influenced by other factors such as snowpack characteristics, wind patterns, and local meteorological conditions.

The findings confirm the key role of albedo and shortwave radiation balance in the melting of low-altitude glaciers.