Permafrost degradation at two monitored palsa mires in north-west Finland
Palsas and peat plateaus are expected to disappear from many regions, including Finnish Lapland. However, detailed long-term monitoring data of the degradation process on palsas are scarce. Here, we present the results of the aerial photography time series analysis (1959–2021), annual real-time kine...
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2023
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ftunivhannover:oai:www.repo.uni-hannover.de:123456789/14255 2023-07-30T03:55:25+02:00 Permafrost degradation at two monitored palsa mires in north-west Finland Verdonen, Mariana Störmer, Alexander Lotsari, Eliisa Korpelainen, Pasi Burkhard, Benjamin Colpaert, Alfred Kumpula, Timo 2023 https://www.repo.uni-hannover.de/handle/123456789/14255 https://doi.org/10.15488/14141 eng eng Katlenburg-Lindau : Copernicus DOI:https://doi.org/10.5194/tc-17-1803-2023 ESSN:1994-0424 http://dx.doi.org/10.15488/14141 https://www.repo.uni-hannover.de/handle/123456789/14255 CC BY 4.0 Unported https://creativecommons.org/licenses/by/4.0 frei zugänglich Cryosphere, The (TC) 17 (2023), Nr. 5 Cryosphere, The (TC) Finland active layer aerial photograph climate effect land degradation ddc:910 status-type:publishedVersion doc-type:Article doc-type:Text 2023 ftunivhannover https://doi.org/10.15488/1414110.5194/tc-17-1803-2023 2023-07-16T22:45:39Z Palsas and peat plateaus are expected to disappear from many regions, including Finnish Lapland. However, detailed long-term monitoring data of the degradation process on palsas are scarce. Here, we present the results of the aerial photography time series analysis (1959–2021), annual real-time kinematic (RTK) GNSS and active layer monitoring (2007–2021), and annual unoccupied aerial system surveys (2016–2021) at two palsa sites (Peera and Laassaniemi, 68∘ N) located in north-west Finland. We analysed temporal trends of palsa degradation and their relation to climate using linear regression. At both sites, the decrease in palsa area by −77 % to −90 % since 1959 and height by −16 % to −49 % since 2007 indicate substantial permafrost degradation throughout the study periods. The area loss rates are mainly connected to winter air temperature changes at Peera and winter precipitation changes at Laassaniemi. The active layer thickness (ALT) has varied annually between 2007 and 2021 with no significant trend and is related mainly to the number of very warm days during summer, autumn rainfall of previous year, and snow depths at Peera. At Laassaniemi, the ALT is weakly related to climate and has been decreasing in the middle part of the palsa during the past 8 years despite the continuous decrease in palsa volume. Our findings imply that the ALT in the inner parts of palsas do not necessarily reflect the overall permafrost conditions and underline the importance of surface position monitoring alongside the active layer measurements. The results also showed a negative relationship between the ALT and snow cover onset, indicating the complexity of climate–permafrost feedbacks in palsa mires. Article in Journal/Newspaper Active layer monitoring Active layer thickness palsa palsas Peat permafrost Lapland Institutional Repository of Leibniz Universität Hannover |
institution |
Open Polar |
collection |
Institutional Repository of Leibniz Universität Hannover |
op_collection_id |
ftunivhannover |
language |
English |
topic |
Finland active layer aerial photograph climate effect land degradation ddc:910 |
spellingShingle |
Finland active layer aerial photograph climate effect land degradation ddc:910 Verdonen, Mariana Störmer, Alexander Lotsari, Eliisa Korpelainen, Pasi Burkhard, Benjamin Colpaert, Alfred Kumpula, Timo Permafrost degradation at two monitored palsa mires in north-west Finland |
topic_facet |
Finland active layer aerial photograph climate effect land degradation ddc:910 |
description |
Palsas and peat plateaus are expected to disappear from many regions, including Finnish Lapland. However, detailed long-term monitoring data of the degradation process on palsas are scarce. Here, we present the results of the aerial photography time series analysis (1959–2021), annual real-time kinematic (RTK) GNSS and active layer monitoring (2007–2021), and annual unoccupied aerial system surveys (2016–2021) at two palsa sites (Peera and Laassaniemi, 68∘ N) located in north-west Finland. We analysed temporal trends of palsa degradation and their relation to climate using linear regression. At both sites, the decrease in palsa area by −77 % to −90 % since 1959 and height by −16 % to −49 % since 2007 indicate substantial permafrost degradation throughout the study periods. The area loss rates are mainly connected to winter air temperature changes at Peera and winter precipitation changes at Laassaniemi. The active layer thickness (ALT) has varied annually between 2007 and 2021 with no significant trend and is related mainly to the number of very warm days during summer, autumn rainfall of previous year, and snow depths at Peera. At Laassaniemi, the ALT is weakly related to climate and has been decreasing in the middle part of the palsa during the past 8 years despite the continuous decrease in palsa volume. Our findings imply that the ALT in the inner parts of palsas do not necessarily reflect the overall permafrost conditions and underline the importance of surface position monitoring alongside the active layer measurements. The results also showed a negative relationship between the ALT and snow cover onset, indicating the complexity of climate–permafrost feedbacks in palsa mires. |
format |
Article in Journal/Newspaper |
author |
Verdonen, Mariana Störmer, Alexander Lotsari, Eliisa Korpelainen, Pasi Burkhard, Benjamin Colpaert, Alfred Kumpula, Timo |
author_facet |
Verdonen, Mariana Störmer, Alexander Lotsari, Eliisa Korpelainen, Pasi Burkhard, Benjamin Colpaert, Alfred Kumpula, Timo |
author_sort |
Verdonen, Mariana |
title |
Permafrost degradation at two monitored palsa mires in north-west Finland |
title_short |
Permafrost degradation at two monitored palsa mires in north-west Finland |
title_full |
Permafrost degradation at two monitored palsa mires in north-west Finland |
title_fullStr |
Permafrost degradation at two monitored palsa mires in north-west Finland |
title_full_unstemmed |
Permafrost degradation at two monitored palsa mires in north-west Finland |
title_sort |
permafrost degradation at two monitored palsa mires in north-west finland |
publisher |
Katlenburg-Lindau : Copernicus |
publishDate |
2023 |
url |
https://www.repo.uni-hannover.de/handle/123456789/14255 https://doi.org/10.15488/14141 |
genre |
Active layer monitoring Active layer thickness palsa palsas Peat permafrost Lapland |
genre_facet |
Active layer monitoring Active layer thickness palsa palsas Peat permafrost Lapland |
op_source |
Cryosphere, The (TC) 17 (2023), Nr. 5 Cryosphere, The (TC) |
op_relation |
DOI:https://doi.org/10.5194/tc-17-1803-2023 ESSN:1994-0424 http://dx.doi.org/10.15488/14141 https://www.repo.uni-hannover.de/handle/123456789/14255 |
op_rights |
CC BY 4.0 Unported https://creativecommons.org/licenses/by/4.0 frei zugänglich |
op_doi |
https://doi.org/10.15488/1414110.5194/tc-17-1803-2023 |
_version_ |
1772811453493936128 |