Reply on RC1

Abstract

The China-Pakistan Economic Corridor (CPEC) is one of flagship projects of the One Belt One Road Initiative, which faces threats from mountain disasters in the high altitude region, such as glacial lake outburst floods (GLOFs). An up-to-date high-quality glacial lake dataset with critical parameters (e.g. lake types), which is fundamental to flood risk assessments and predicting glacier-lake evolutions, is still largely absent for the entire CPEC. This study describes a glacial lake dataset in 2020 for CPEC at 10–30 m resolution, which was produced from both Landsat and Sentinel optical images as well as glacial lake inventories in 1990 and 2000 from Landsat observation, using an advanced object-oriented mapping method associated with rigorous visual inspection workflows. The results show that Landsat derived 2234 glacial lakes in 2020, covering a total area of 86.31 ± 14.98 km2 with a minimum mapping unit of 5 pixels (4500 m2), whereas Sentinel derived 7560 glacial lakes in 2020 with a total area of 103.70 ± 8.45 km2 with a minimum mapping unit of 5 pixels (500 m2). The discrepancy implies that there is a significant quantity of small glacier lakes not recognized in existing glacial lake inventories and a more thorough inclusion of them require future efforts using higher resolution data. The total number and area of glacial lakes from consistent 30 m resolution Landsat images remain relatively stable despite a slight increase from 1990 to 2020. A range of critical attributes have been generated in the dataset, including lake types of two classification systems and mapping uncertainty estimated by an improved equation. This comprehensive glacial lake dataset has potentials to be widely applied in studies on glacial lake-related hazards and glacier-lake interactions, and is freely available at https://doi.org/10.12380/Glaci.msdc.000001 (Lesi et al., 2022).