| Title | Long-term ice-rich permafrost coast sensitivity to air temperatures and storm influence: lessons from Pullen Island, Northwest Territories, Canada |
| |
| Author | Berry, H B; Whalen, D ; Lim, M |
| Source | Arctic Science vol. 7, issue 4, 2021 p. 723-745, https://doi.org/10.1139/as-2020-0003  Open Access |
| Image |  |
| Year | 2021 |
| Alt Series | Natural Resources Canada, Contribution Series 20200675 |
| Publisher | Canadian Science Publishing |
| Document | serial |
| Lang. | English |
| Media | paper |
| File format | pdf; html |
| Province | Northwest Territories |
| Area | Pullen Island; Canada |
| Lat/Long WENS | -138.3333 -131.3333 70.1667 68.2500 |
| Subjects | Science and Technology; general geology; coastal erosion; permafrost; Climate change; Arctic |
| Illustrations | location maps; satellite images; charts; diagrams; photographs |
| Program | Climate Change Geoscience Coastal Infrastructure |
| Released | 2021 01 29 |
| Abstract | The potential effects of climate change on the length of the open-water season, storm activity, and annual permafrost thaw have raised concerns over the future of the Beaufort Sea permafrost coasts,
which already have some of the highest erosion rates in the Arctic. The research examines a marked acceleration in cliff retreat rate in the outer Mackenzie Delta (Pullen Island) over a 71-year period based on aerial photogrammetry and historic
imagery. Block collapse from notch development in sub-vertical cliffs and slumping from sprawling thaw complexes are the two predominant failure mechanisms governing coastal erosion in this region. Using a combination of aerial imagery and ground
survey data we show mean erosion rates increased from 0 + 4.8 m/a in 1947 to 12 + 0.3 m/a in 2018. The rate of cliff line retreat also became more varied through time. The erosion responses are positively correlated with summer air temperature; this
relationship has a stronger correlation coefficient in areas where slumping is the dominant erosive mechanism compared to areas where block failure is dominant (r2 = 0.08), and compared to the mean rate for the entire study area (r2 = 0.34).
Similarly, there is a significant positive correlation between storm duration and the rate of retreat, which is stronger in areas where the dominant mechanism is block failure compared to areas where slumping is dominant.. These data indicate that
storm duration has the greatest impact on these ice-rich permafrost coasts and most acutely on areas undergoing block failures, whilst air temperature has a greater impact on slump-dominated areas than elsewhere along the coast. The increase in
heterogeneity of the cliff retreat rate is likely a result of different magnitudes of response to the increase in summer air temperatures and storm duration depending on erosive mechanism, and on the morphological differences such as cliff height and
ground ice occurrence, which prescribe the occurrence of retrogressive thaw slumps. |
| GEOSCAN ID | 327959 |
|
|