5:15 PM - 6:45 PM
[ACC26-P06] Formation factors of short-lived glacial lakes in the northern Tien Shan.
Keywords:short-lived glacial lake, glacial lake outburst flood, Tien shan Mountains, ice tunnel
To elucidate the storage volume changes of the Korumdu glacial lake from 2015 to 2023, daily volume changes were calculated using a DSM created from UAV aerial images, with area changes in unobserved years inferred from PlanetScope satellite images (resolution 3m) and volume changes from the DSM. The degree-day method was employed to calculate the melting volume of glaciers adjacent to the lake, using temperature data observed at hourly intervals at the glacier terminus. Additionally, the degree-day factor (DDF) was calculated from melt depth measurements.
The results for 2023 indicate that the glacier melt volume and the glacial lake volume began to increase significantly in early June when temperatures rose well above 0°C. After the lake expanded, its volume began to decrease from August 8th, and by late August, the lake had disappeared entirely. The formation and disappearance of the lake occurred over approximately three weeks each. In years other than 2020, when the lake appeared, the timing of its appearance was between July and mid-August, but the maximum volume varied from year to year. An examination of the variations in glacier melt volume (inflow to the lake), lake storage volume, and outflow from the lake confirmed that the formation of the lake begins when inflow exceeds drainage. However, the calculation of the lake's storage volume using the outflow during the lake's expansion phase did not match the rapid volume change in 2017, suggesting that the lake's formation might be influenced not only by an increase in glacier melt but also by a reduction in drainage due to tunnel closure.
The results for 2023 indicate that the glacier melt volume and the glacial lake volume began to increase significantly in early June when temperatures rose well above 0°C. After the lake expanded, its volume began to decrease from August 8th, and by late August, the lake had disappeared entirely. The formation and disappearance of the lake occurred over approximately three weeks each. In years other than 2020, when the lake appeared, the timing of its appearance was between July and mid-August, but the maximum volume varied from year to year. An examination of the variations in glacier melt volume (inflow to the lake), lake storage volume, and outflow from the lake confirmed that the formation of the lake begins when inflow exceeds drainage. However, the calculation of the lake's storage volume using the outflow during the lake's expansion phase did not match the rapid volume change in 2017, suggesting that the lake's formation might be influenced not only by an increase in glacier melt but also by a reduction in drainage due to tunnel closure.