| Titre | Effective monitoring of permafrost coast erosion: wide-scale storm impacts on outer islands in the Mackenzie Delta Area |
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| Auteur | 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  Accès ouvert |
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| Année | 2020 |
| Séries alt. | Ressources naturelles Canada, Contribution externe 20200532 |
| Éditeur | Frontiers Media S.A. |
| Document | publication en série |
| Lang. | anglais |
| DOI | https://doi.org/10.3389/feart.2020.561322 |
| Media | papier; en ligne; numérique |
| Formats | pdf; html |
| Province | Territoires du Nord-Ouest |
| SNRC | 107C/05; 107C/06; 107C/07; 107C/10; 107C/11; 107C/12 |
| Région | Fleuve Mackenzie; Mer de Beaufort; Tuktoyaktuk Peninsula; Peninsula Point; Pelly Island; Hooper Island; Pullen Island |
| Lat/Long OENS | -136.0000 -133.0000 69.8333 69.2500 |
| Sujets | milieu côtièr; érosion côtière; pergélisol; glace fossile; glace massive; tempêtes; climat arctique; effets climatiques; glissements de terrain; glissements; coulées de débris; cônes de déjection;
glissements de pentes; télédétection; levés photogrammétriques; sensitivité de terrain; modèles; techniques de cartographie; Changement climatique; effets cumulatifs; Temps (Météorologie); dégel du pergélisol; géologie des dépôts
meubles/géomorphologie; géologie de l'environnement; géophysique; Nature et environnement; Sciences et technologie |
| Illustrations | cartes de localisation; diagrammes 3D; modèles; tableaux; images 3D; profils; séries chronologiques |
| Programme | Géosciences de changements climatiques, Infrastructure côtière |
| Diffusé | 2020 10 08 |
| Résumé | (disponible en anglais seulement)
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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