Publication Date:
2017-03-24
Description:
The glaciers of the Cordillera Blanca Peru are rapidly retreating as a result of climate change, altering 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 asl) 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 melt water 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 simple measurements of changes in aerial extent are inadequate for understanding actual changes in glacier ice quantity.
Print ISSN:
1994-0432
Electronic ISSN:
1994-0440
Topics:
Geography
,
Geosciences