Publication Date:
2023-07-25
Description:
Repeat images present an opportunity to document land use and land cover changes in a visually appealing way; they tell a story easy to understand by the broader audience. Overlapping series of oblique aerial photos allow for a photogrammetric analysis and the generation of digital elevation models (DEMs). We compared oblique aerial photographs from 1931 with Google Earth satellite images to describe glacier changes in the Cordillera Vilcanota in the Andes of Peru. As no flight logbook from 1931 was available, we first recreated the 1931 flight path using Google Earth, and then matched the historical photos with Google Earth views. The comparison of ice coverage in the photo pairs was carried out using Pixcavator, and 1931 DEMs were generated for parts of the range in Agisoft Metashape. Across the Vilcanota Range, the ice cover decreased by 45% in the 90 years since 1931. In contrast, a comparison of a few glacial lakes covered by the 1931 photos did not reveal any significant change in area. However, a multitemporal analysis using satellite imagery documented an increase in glacial lakes by 175 from 152 in 1966 to 327 in 2021, and an increase in total glacial lake area by 14.3 km〈sup〉2〈/sup〉 from 9.3 km〈sup〉2〈/sup〉 in 1966 to 23.7 km〈sup〉2〈/sup〉 in 2021. We will repeat the 1931 photographs using a charted airplane and unmanned aerial vehicles (UAVs) during a field campaign in summer of 2023. The comparison of 1931 with 2023 DEMs will allow for an estimation of glacier mass change.
Language:
English
Type:
info:eu-repo/semantics/conferenceObject
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