The shifting mosaic of ice-wedge degradation and stabilization in response to infrastructure and climate change, Prudhoe Bay Oilfield, Alaska, USA

Arctic Science

article

Mikhail Kanevskiy¹  Yuri Shur¹  D.A. (Skip) Walker²  Torre Jorgenson³  Martha K. Raynolds²  Jana L. Peirce²  Benjamin M. Jones¹  Marcel Buchhorn⁴  Georgiy Matyshak⁵  Helena Bergstedt¹  Amy L. Breen⁶  Billy Connor¹  Ronald Daanen⁷  Anna Liljedahl⁸  Vladimir E. Romanovsky⁹  Emily Watson-Cook² 

[1] Institute of Northern Engineering, University of Alaska Fairbanks;Institute of Arctic Biology, University of Alaska Fairbanks;Alaska Ecoscience;VITO;Department of Soil Science, Lomonosov Moscow State University;International Arctic Research Center, University of Alaska Fairbanks;Alaska Department of Natural Resources, Geological and Geophysical Surveys;Woodwell Climate Research Center;Geophysical Institute, University of Alaska Fairbanks

关键词: permafrost;    thermokarst;    ground ice;    cryostratigraphy;    active layer;    transient layer;    intermediate layer.;   

DOI  :  10.1139/as-2021-0024

学科分类：地球科学(综合)

来源: NRC Research Press

【 摘 要 】

We studied processes of ice-wedge degradation and stabilization at three sites adjacent to road infrastructure in the Prudhoe Bay Oilfield, Alaska, USA. We examined climatic, environmental, and subsurface conditions and evaluated vulnerability of ice wedges to thermokarst in undisturbed and road-affected areas. Vulnerability of ice wedges strongly depends on the structure and thickness of soil layers above ice wedges, including the active, transient, and intermediate layers. In comparison with the undisturbed area, sites adjacent to the roads had smaller average thicknesses of the protective intermediate layer (4 cm vs. 9 cm), and this layer was absent above almost 60% of ice wedges (vs. ∼45% in undisturbed areas). Despite the strong influence of infrastructure, ice-wedge degradation is a reversible process. Deepening of troughs during ice-wedge degradation leads to a substantial increase in mean annual ground temperatures but not in thaw depths. Thus, stabilization of ice wedges in the areas of cold continuous permafrost can occur despite accumulation of snow and water in the troughs. Although thermokarst is usually more severe in flooded areas, higher plant productivity, more litter, and mineral material (including road dust) accumulating in the troughs contribute to formation of the intermediate layer, which protects ice wedges from further melting.

【 授权许可】

CC BY