Delineation Evaluation and Variation of Debris-Covered Glaciers Based on the Multi-Source Remote Sensing Images, Take Glaciers in the Eastern Tomur Peak Region for Example

As a particular type of alpine glacier, debris-covered glaciers are essential for local water resources and glacial disaster warnings. The Eastern Tomur Peak Region (EPTR) is the most concentrated glacier in Tien Shan Mountain, China, where the glaciers have not been studied in detail. This paper evaluates the delineation accuracy of Landsat8 OLI, Sentinel-1A, and GF images for debris-covered glaciers in the EPTR. Each image uses the most advanced delineation method for itself to minimize the error of inherent resolutions. The results show that the accuracy of these images for delineating debris-covered glaciers is very high, and the F1 scores are expressed as 96.73%, 93.55%, and 95.81%, respectively. Therefore, Landsat images were selected to analyze the area change of EPTR from 2000 to 2022 over a 5-year time scale. The results indicate that glaciers of the EPTR decreased by 19.05 km(2) from 2000 to 2020, accounting for 1.9% (0.08% a(-1)), and debris increased by 10.8%, which validates the opinion that the presence of debris inhibits glacier melting. The most varied time was 2010-2022, but it was much less than other Tien Shan regions. The lower glacier ablation rate in this area results from the combined effect of decreased bare ice and increased debris. The main reason for the change in debris-covered glaciers is the increase in temperature.

Automated summary

This study evaluates the accuracy of Landsat8 OLI, Sentinel-1A, and GF images in delineating debris-covered glaciers in the Eastern Tomur Peak Region (EPTR) of the Tien Shan Mountain. The results show that these images have high accuracy in delineating debris-covered glaciers, with F1 scores of 96.73%, 93.55%, and 95.81%, respectively. The analysis of area change using Landsat images from 2000 to 2022 reveals a decrease in glacier area and an increase in debris-covered area, confirming the inhibitory effect of debris on glacier melting. The main driver of change in debris-covered glaciers is the increase in temperature.