A spatiotemporally constrained inventory of global glacial lakes

Climate change accelerates the extensive retreat and downwasting of glaciers, leading to the widespread formations and rapid growths of glacial lakes worldwide. Spatial distribution information on glacial lakes is crucial for evidencing the climate change impacts and warning about the hazards of glacial lake outbursts. The existing glacial lake inventories are mostly region or basin specific. Therefore, there is therefore a pressing need to obtain a spatially and temporally constrained dataset of global glacial lakes. Based on a semi-automated approach, this study inventories 117,352 glacial lakes (≥0.01 km2) worldwide, with a net area of 24,755.84 ± 2,971.33 km2. The evaluation result shows that the global glacial lake data have an average overall accuracy of 89.37% and 91.42% in number and area, respectively. The global glacial lakes are widely distributed in different altitudes, ranging from the Earth’s third pole to the coastal zones. Most glacial lakes are distributed in Greenland, High-Mountain Asia (HMA), Alaska, western and northern Canada, and the cordilleras. The number and total area of glacial lakes located at the altitude below 1000 m account for 59.35% and 82.84%, respectively, whereas the lakes spanning more than 3000 m are dominantly observed in HMA. The number of glacial lakes between 0.01–0.1 km2 accounts for 77.24% of the total count but only 11.82% of the total area. The classification of glacial lakes as four groups (non–glacier-fed, ice-uncontacted proglacial, ice-contacted proglacial, and supraglacial lakes) indicates that the ice-uncontacted proglacial lakes dominate the number (67.07%) and area (53.04%) worldwide. This dataset is expected to advance the monitoring of glacial lake expansions and the assessment of glacial hazard risk.气候变化加速了冰川的大规模退缩与厚度减薄，进而在全球范围内引发冰川湖（glacial lakes）的广泛形成与快速扩张。冰川湖的空间分布信息，对于佐证气候变化影响以及预警冰湖溃决灾害具有重要意义。现有冰川湖编目大多针对特定区域或流域，因此亟需构建一套具备时空约束性的全球冰川湖数据集。 本研究采用半自动化方法，对全球范围内面积≥0.01 km²的117352处冰川湖进行了编目，其总面积为24755.84±2971.33 km²。评估结果显示，该全球冰川湖数据集在数量与面积上的总体平均准确率分别为89.37%和91.42%。 全球冰川湖分布于不同海拔区间，覆盖范围从地球第三极直至沿海区域。冰川湖主要分布于格陵兰、高亚洲（High-Mountain Asia, HMA）、阿拉斯加、加拿大西部与北部以及科迪勒拉山系。海拔低于1000米的冰川湖数量与总面积分别占总量的59.35%和82.84%，而海拔超过3000米的冰川湖则主要集中于高亚洲区域。面积介于0.01~0.1 km²的冰川湖数量占总数量的77.24%，但其总面积仅占总冰川湖面积的11.82%。 本研究将冰川湖划分为四类：非冰川补给湖（non–glacier-fed）、未接触冰体的冰前湖（ice-uncontacted proglacial）、接触冰体的冰前湖（ice-contacted proglacial）以及冰面湖（supraglacial lakes）。分析结果显示，未接触冰体的冰前湖在全球冰川湖的数量（67.07%）与面积（53.04%）上均占主导地位。 该数据集有望推动冰川湖扩张监测与冰湖灾害风险评估相关研究的发展。