Ice thickness and morphological analysis reveal the future glacial lake distribution and formation probability in the Tibetan Plateau and its surroundings

Owing to intense glacial retreat and melting, it is anticipated that numerous glacial lakes will be formed in the next few decades. However, their development and distribution patterns in the Tibetan Plateau and its surroundings still need to be elucidated. In this study, a published glacier ice thickness distribution dataset was employed to fully detect overdeepened glacier beds as potential glacial lakes. We selected and expanded four morphological metrics to determine the formation probability of potential glacial lakes: surface slope, break in slope, lake area, and position on the glacier. The results revealed that 15,826 potential glacial lakes with areas > 0.02 km(2) exist in the Tibetan Plateau and its surroundings, covering an area of 2253.95 +/- 1291.29 km(2) with a water volume of 60.49 +/- 28.94 km(3) that would contribute to an equivalent sea level rise of 0.16 +/- 0.08 mm. The experimental comparison and uncertainty assessment for the overdeepening processing showed that the different extraction methods and basic digital elevation models used could lead to non-negligible errors in the results (at least +/- 30%), which were ignored in previous studies, contributing to major divergences between the several current inventories of potential glacial lakes in the plateau. Notably, approximately 90% of the total area of the potential glacial lakes is concentrated in the lower half of the individual glaciers in the Tibetan Plateau and its surroundings. > 70% of the potential glacial lakes and contemporary glacial lakes in this region were found to be concentrated within the 4000-5800 m elevation range. Moreover, the study identified 5361 potential glacial lakes with high or very high exposure probabilities, and their distribution was mostly determined by regional glacier resources. However, the numbers and sizes of some potential glacial lakes that are found in the Karakoram region are considered to be exaggerated because of the presence of numerous surge-type glaciers, which have not been discussed in previous studies. These results can improve our understanding of future glacial lake formation and distribution in the Tibetan Plateau and its surroundings and have implications for further implementation of effective prevention, mitigation, and adaptation measures for glacial lake outburst floods and water security.

Automated summary

This study used a glacier ice thickness distribution dataset to identify potential glacial lakes in the Tibetan Plateau and its surroundings. The study found a significant number of potential glacial lakes and provided morphological metrics to determine their formation probability. The results also highlighted the concentration of these lakes in the lower half of individual glaciers and within a specific elevation range. The findings contribute to our understanding of future glacial lake formation and distribution in the region and have important implications for flood prevention and water security measures.