Geophysical imaging and thermal modeling of subsurface morphology and thaw evolution of discontinuous permafrost
Alastair McClymont,Alastair McClymont,Masaki Hayashi,Laurence R. Bentley,Brendan S. Christensen +4 more
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In this paper, the authors show how the land cover distributions influence thawing of discontinuous permafrost at a study site in the Northwest Territories, Canada using electrical resistivity tomography, ground-penetrating radar profiling, and thermal-conduction modeling.Abstract:
[1] Despite our current understanding of permafrost thaw in subarctic regions in response to rising air temperatures, little is known about the subsurface geometry and distribution of discontinuous permafrost bodies in peat-covered, wetland-dominated terrains and their responses to rising temperature Using electrical resistivity tomography, ground-penetrating radar profiling, and thermal-conduction modeling, we show how the land cover distributions influence thawing of discontinuous permafrost at a study site in the Northwest Territories, Canada Permafrost bodies in this region occur under forested peat plateaus and have thicknesses of 5–13 m Our geophysical data reveal different stages of thaw resulting from disturbances within the active layer: from widening and deepening of differential thaw features under small frost-table depressions to complete thaw of permafrost under an isolated bog By using two-dimensional geometric constraints derived from our geophysics profiles and meteorological data, we model seasonal and interannual changes to permafrost distribution in response to contemporary climatic conditions and changes in land cover Modeling results show that in this environment (1) differences in land cover have a strong influence on subsurface thermal gradients such that lateral thaw dominates over vertical thaw and (2) in accordance with field observations, thaw-induced subsidence and flooding at the lateral margins of peat plateaus represents a positive feedback that leads to enhanced warming along the margins of peat plateaus and subsequent lateral heat conduction Based on our analysis, we suggest that subsurface energy transfer processes (and feedbacks) at scales of 1–100 m have a strong influence on overall permafrost degradation rates at much larger scalesread more
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Hydrologic impacts of thawing permafrost—A review
TL;DR: In this article, the authors highlight promising advances in characterization and modeling of permafrost regions and present ongoing research challenges toward projecting hydrologic and ecologic consequences of permaferost thaw at time and spatial scales that are useful to managers and researchers.
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Transitions in Arctic ecosystems: Ecological implications of a changing hydrological regime
Frederick J. Wrona,Margareta Johansson,Joseph M. Culp,Alan Jenkins,Johanna Mård,Isla H. Myers-Smith,Terry D. Prowse,Warwick F. Vincent,Philip A. Wookey +8 more
TL;DR: In this article, the terrestrial and freshwater ecology component of the Arctic Freshwater Synthesis is reviewed and recommended enhanced coordinated circumpolar research and monitoring efforts to improve quantification and prediction of how an altered hydrological regime influences local, regional, and circumpheric-level responses in terrestrial and freshwater systems.
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Changing hydrologic connectivity due to permafrost thaw in the lower Liard River valley, NWT, Canada
TL;DR: In this article, the authors examined streamflow changes in the four Water Survey of Canada gauged river basins (152,2050,km2) in the lower Liard River valley, Northwest Territories, Canada, a region where permafrost thaw has produced widespread loss of forest and concomitant expansion of permaferost-free wetlands.
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Influence of vertical and lateral heat transfer on permafrost thaw, peatland landscape transition, and groundwater flow
TL;DR: In this article, the authors investigated fundamental processes that contribute to permafrost thaw by comparing observed and simulated thaw development and landscape transition of a peat plateau-wetland complex in the Northwest Territories, Canada from 1970 to 2012.
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The Influence of Shallow Taliks on Permafrost Thaw and Active Layer Dynamics in Subarctic Canada
TL;DR: In this paper, the authors demonstrate that the entire thickness of ground atop permafrost does not always refreeze over winter, and that the presence of taliks greatly affects the stability of the underlying ground.
References
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Resilience and vulnerability of permafrost to climate change
M. Torre Jorgenson,Vladimir Romanovsky,Jennifer Harden,Y. Shur,Jonathan O’DonnellJ. O’Donnell,Edward A. G. Schuur,Mikhail Kanevskiy,S. Marchenko +7 more
TL;DR: The resilience and vulnerability of permafrost to climate change depends on complex interactions among topography, water, soil, vegetation, and snow, which allow permaf frost to persist at mean annua...
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Cross-hole electrical imaging of a controlled saline tracer injection
TL;DR: In this paper, a tracer was injected into a tank facility (dimensions 10×10×3 m) consisting of alternating sand and clay layers and the pixels that make up the electrical images were interpreted as a large number of breakthrough curves.
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Accelerated thawing of subarctic peatland permafrost over the last 50 years
TL;DR: In this article, the authors provide a quantification of the main patterns of change of a subarctic peatland caused by permafrost decay monitored between 1957 and 2003.
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A comparison of the Gauss–Newton and quasi-Newton methods in resistivity imaging inversion
M. H. Loke,Torleif Dahlin +1 more
TL;DR: In this paper, the smoothness-constrained least-squares method is used for two-dimensional and three-dimensional (3D) inversion of apparent resistivity data sets.
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Increasing winter baseflow and mean annual streamflow from possible permafrost thawing in the Northwest Territories, Canada
TL;DR: In this article, a statistically significant positive link between the Northern annular mode and annual NWT streamflow at the interannual-to-decadal timescales was presented.