Monitoring tropical debris-covered glacier dynamics from high-resolution unmanned aerial vehicle photogrammetry, Cordillera Blanca, Peru
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 glacie...
| Main Authors: | , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2017-11-01
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| Series: | The Cryosphere |
| Online Access: | https://www.the-cryosphere.net/11/2463/2017/tc-11-2463-2017.pdf |
| Summary: | 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.<br><br>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. |
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| ISSN: | 1994-0416 1994-0424 |