Post-fire stabilization of thaw-affected permafrost terrain in northern Alaska

In 2007, the Anaktuvuk River fire burned more than 1000 km 2 of arctic tundra in northern Alaska, ~ 50% of which occurred in an area with ice-rich syngenetic permafrost (Yedoma). By 2014, widespread degradation of ice wedges was apparent in the Yedoma region. In a 50 km 2 area, thaw subsidence was d...

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Published in:Scientific reports Vol. 14; no. 1; pp. 8499 - 12
Main Authors: Jones, Benjamin M., Kanevskiy, Mikhail Z., Shur, Yuri, Gaglioti, Benjamin V., Jorgenson, M. Torre, Ward Jones, Melissa K., Veremeeva, Alexandra, Miller, Eric A., Jandt, Randi
Format: Journal Article
Language:English
Published: London Nature Publishing Group UK 11.04.2024
Nature Publishing Group
Nature Portfolio
Subjects:
704/106
704/172
Cores
Humanities and Social Sciences
Ice
Lidar
multidisciplinary
Permafrost
Rivers
Science
Science (multidisciplinary)
Soil surfaces
Subsidence
Temperature measurement
Thawing
Tundra
Unconformity
United States > US
Alaska
ISSN:2045-2322, 2045-2322
Online Access:Get full text
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Summary:In 2007, the Anaktuvuk River fire burned more than 1000 km 2 of arctic tundra in northern Alaska, ~ 50% of which occurred in an area with ice-rich syngenetic permafrost (Yedoma). By 2014, widespread degradation of ice wedges was apparent in the Yedoma region. In a 50 km 2 area, thaw subsidence was detected across 15% of the land area in repeat airborne LiDAR data acquired in 2009 and 2014. Updating observations with a 2021 airborne LiDAR dataset show that additional thaw subsidence was detected in < 1% of the study area, indicating stabilization of the thaw-affected permafrost terrain. Ground temperature measurements between 2010 and 2015 indicated that the number of near-surface soil thawing-degree-days at the burn site were 3 × greater than at an unburned control site, but by 2022 the number was reduced to 1.3 × greater. Mean annual ground temperature of the near-surface permafrost increased by 0.33 °C/yr in the burn site up to 7-years post-fire, but then cooled by 0.15 °C/yr in the subsequent eight years, while temperatures at the control site remained relatively stable. Permafrost cores collected from ice-wedge troughs (n = 41) and polygon centers (n = 8) revealed the presence of a thaw unconformity, that in most cases was overlain by a recovered permafrost layer that averaged 14.2 cm and 18.3 cm, respectively. Taken together, our observations highlight that the initial degradation of ice-rich permafrost following the Anaktuvuk River tundra fire has been followed by a period of thaw cessation, permafrost aggradation, and terrain stabilization.
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ISSN:2045-2322
2045-2322
DOI:10.1038/s41598-024-58998-5