Monitoring tropical debris-covered glacier dynamics from high-resolution unmanned aerial vehicle photogrammetry, Cordillera Blanca, Peru
Monitoring tropical debris-covered glacier dynamics from high-resolution unmanned aerial vehicle photogrammetry, Cordillera Blanca, Peru
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DOI：
10.5194/tc-11-2463-2017
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发表时间：
2017-11
期刊：
影响因子：
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通讯作者：
O. Wigmore;B. Mark
中科院分区：
文献类型：
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作者：
O. Wigmore;B. Mark
抽象的。由于气候变化，秘鲁布兰卡山脉的冰川正在迅速退缩和变薄，改变了下游用户可用水的时间、数量和质量。此外，与这些冰川融化相关的前冰湖数量和规模的增加正在增加遭受冰川湖溃决洪水（GLOF）的潜在风险。因此，了解这些冰川如何变化以及它们与前冰川湖系统的联系至关重要。大多数卫星数据对于研究小型山地冰川来说过于粗糙，并且经常受到云层的影响，而传统的机载摄影测量和激光雷达成本高昂。最近的发展使无人机（UAV）成为一种可行且具有潜在变革性的方法，可用于以高空间分辨率、按需且相对较低的成本研究冰川变化。我们使用专为高空（4000-6000 m a. s. l.）作业而定制设计的六轴飞行器，完成了对被碎片覆盖的拉卡冰川舌和前冰湖系统的重复航空调查（2014 年和 2015 年）。制作了高分辨率正射马赛克 (5 厘米) 和数字高程模型 (DEM) (10 厘米)，并评估了它们的准确性。对这些数据集的分析揭示了冰川变化的高度异质模式。冰流失最快的区域与冰川表面暴露的冰崖和融水池有关。在前冰川湖内的沉积物上还测量到相当大的沉降和低表面速度，表明存在大范围的埋冰区域并与冰川舌持续相连。仅观察到冰川舌的水平退缩有限，这表明仅测量空中范围的变化不足以监测冰川冰量的变化。
Abstract. The glaciers of the Cordillera Blanca, Peru, are rapidly retreating and thinning as a result of climate change, altering the timing, quantity and quality of water available to downstream users. Furthermore, increases in the number and size of proglacial lakes associated with these melting glaciers is increasing potential exposure to glacier lake outburst floods (GLOFs). Understanding how these glaciers are changing and their connection to proglacial lake systems is thus of critical importance. Most satellite data are too coarse for studying small mountain glaciers and are often affected by cloud cover, while traditional airborne photogrammetry and lidar are costly. Recent developments have made unmanned aerial vehicles (UAVs) a viable and potentially transformative method for studying glacier change at high spatial resolution, on demand and at relatively low cost. Using a custom designed hexacopter built for high-altitude (4000–6000 m a. s. l. ) operation, we completed repeat aerial surveys (2014 and 2015) of the debris-covered Llaca Glacier tongue and proglacial lake system. High-resolution orthomosaics (5 cm) and digital elevation models (DEMs) (10 cm) were produced and their accuracy assessed. Analysis of these datasets reveals highly heterogeneous patterns of glacier change. The most rapid areas of ice loss were associated with exposed ice cliffs and meltwater ponds on the glacier surface. Considerable subsidence and low surface velocities were also measured on the sediments within the pro-glacial lake, indicating the presence of extensive regions of buried ice and continued connection to the glacier tongue. Only limited horizontal retreat of the glacier tongue was observed, indicating that measurements of changes in aerial extent alone are inadequate for monitoring changes in glacier ice quantity.