Quantifying Palsa Degradation Dynamics Using UAV Imagery
2024 (English)Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE credits
Student thesisAlternative title
Kvantifiering av palsdegradationsdynamik genom drönarfotografering (Swedish)
Abstract [en]
The widespread degradation of permafrost-cored palsa mires due to global warming necessitates accurate quantification to estimate potential greenhouse gas (GHG) flux changes. This study utilized high-resolution Unmanned Aerial Vehicle (UAV) imagery to quantify palsa degradation dynamics, including lateral, vertical, and geomorphological changes in the Storflaket palsa mire in north-west Sweden. A GIS-based analysis of UAV-derived differential Digital Elevation Models (DEM) between 2016–2023 revealed subsidence on >99 % of the palsa, active lateral erosion, and thermokarst formation. Despite near-double marginal subsidence rates, interior degradation accounted for ~95 % of the total volumetric decrease, attributed to a substantially larger interior area. The mean height, area, and volume changes for the whole palsa were -43.28±7.33 %, -6.66±0.74 %, and -47.00±7.26 %, respectively. However, the large decreases in height and volume are likely overestimations. The geomorphological analysis revealed landform element changes in ~46 % of the palsa and indicated some level of predictability in these changes. The results suggest that palsa degradation induces pronounced local landscape variation, which, in combination with fragmentation, affects the degradation rate. Furthermore, geomorphological changes provide a warning of an impending increase in CH4 emissions at Storflaket. These findings highlight the importance of high-resolution remote sensing techniques to survey palsa degradation dynamics, which is essential to enhance the understanding of these processes and, in continuation, their contribution to GHG fluxes.
Place, publisher, year, edition, pages
2024. , p. 27
Keywords [en]
Permafrost, palsa mire, geomorphology, UAV, climate change
National Category
Earth and Related Environmental Sciences Physical Geography Geosciences, Multidisciplinary
Identifiers
URN: urn:nbn:se:umu:diva-226022OAI: oai:DiVA.org:umu-226022DiVA, id: diva2:1868429
Educational program
Bachelor of Science in Biology and Earthscience
Presentation
BIO.D.252, Johan Bures väg 12, Umeå (Swedish)
Supervisors
Examiners
2024-06-122024-06-112025-01-31Bibliographically approved