| Title | Effective monitoring of permafrost coast erosion: wide-scale storm impacts on outer islands in the Mackenzie Delta Area |
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| Author | Lim, M; Whalen, D ; Mann, P J; Fraser, P; Berry, H B; Irish, C; Cockney, K; Woodward, J |
| Source | Frontiers in Earth Science vol. 8, 561322, 2020 p. 1-17, https://doi.org/10.3389/feart.2020.561322  Open Access |
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| Year | 2020 |
| Alt Series | Natural Resources Canada, Contribution Series 20200532 |
| Publisher | Frontiers Media S.A. |
| Document | serial |
| Lang. | English |
| Media | paper; on-line; digital |
| File format | pdf; html |
| Province | Northwest Territories |
| NTS | 107C/05; 107C/06; 107C/07; 107C/10; 107C/11; 107C/12 |
| Area | Mackenzie River; Beaufort Sea; Tuktoyaktuk Peninsula; Peninsula Point; Pelly Island; Hooper Island; Pullen Island |
| Lat/Long WENS | -136.0000 -133.0000 69.8333 69.2500 |
| Subjects | surficial geology/geomorphology; environmental geology; geophysics; Nature and Environment; Science and Technology; coastal environment; coastal erosion; permafrost; ground ice; massive ice; storms;
climate, arctic; climate effects; landslides; slumps; debris flows; debris fans; slope failures; remote sensing; photogrammetric surveys; terrain sensitivity; models; mapping techniques; Mackenzie Delta; Climate change; cumulative effects; Weather;
permafrost thaw |
| Illustrations | location maps; 3-D diagrams; models; tables; 3-D images; profiles; time series |
| Program | Climate Change Geoscience Coastal Infrastructure |
| Released | 2020 10 08 |
| Abstract | Permafrost coasts are extensive in scale and complex in nature, resulting in particular challenges for understanding how they respond to both long-term shifts in climate and short-term extreme weather
events. Taking examples from the Canadian Beaufort Sea coastline characterized by extensive areas of massive ground ice within slump and block failure complexes, we conduct a quantitative analysis of the practical performance of helicopter-based
photogrammetry. The results demonstrate that large scale (>1 km2) surface models can be achieved at comparable accuracy to standard unmanned aerial vehicle surveys, but 36 times faster. Large scale models have greater potential for progressive
alignment and contrast issues and so breaking down image sequences into coherent chunks has been found the most effective technique for accurate landscape reconstructions. The approach has subsequently been applied in a responsive acquisition
immediately before and after a large storm event and during conditions (wind gusts >50 km h-1) that would have prohibited unmanned aerial vehicle data acquisition. Trading lower resolution surface models for large scale coverage and more effective
responsive monitoring, the helicopter-based data have been applied to assess storm driven-change across the exposed outer islands of the Mackenzie Delta area for the first time. These data show that the main storm impacts were concentrated on exposed
North orientated permafrost cliff sections (particularly low cliffs, >20 m in height) where cliff recession was 43% of annual rates and in places up to 29% of the annual site-wide erosion volume was recorded in this single event. In contrast, the
thaw-slump complexes remained relatively unaffected, debris flow fans were generally more resistant to storm erosion than the ice-rich cliffs, perhaps due to the relatively low amounts of precipitation that occurred. Therefore, the variability of
permafrost coast erosion rates is controlled by interactions between both the forcing conditions and local response mechanisms. Helicopter-based photogrammetric surveys have the potential to effectively analyze these controls with greater spatial and
temporal consistency across more representative scales and resolutions than has previously been achieved, improving the capacity to adequately constrain and ultimately project future Arctic coast sensitivity. |
| GEOSCAN ID | 327569 |
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