Abstract. Permafrost landscapes are changing around the Arctic in response to climate
warming, with coastal erosion being one of the most prominent and hazardous
features. Using drone platforms, satellite images, and historic aerial
photographs, we observed the rapid retreat of a permafrost coastline on
Qikiqtaruk – Herschel Island, Yukon Territory, in the Canadian Beaufort Sea.
This coastline is adjacent to a gravel spit accommodating several culturally
significant sites and is the logistical base for the Qikiqtaruk – Herschel
Island Territorial Park operations. In this study we sought to (i) assess
short-term coastal erosion dynamics over fine temporal resolution,
(ii) evaluate short-term shoreline change in the context of long-term
observations, and (iii) demonstrate the potential of low-cost lightweight
unmanned aerial vehicles (“drones”) to inform coastline studies and
management decisions. We resurveyed a 500 m permafrost coastal reach at high
temporal frequency (seven surveys over 40 d in 2017). Intra-seasonal
shoreline changes were related to meteorological and oceanographic variables
to understand controls on intra-seasonal erosion patterns. To put our
short-term observations into historical context, we combined our analysis of
shoreline positions in 2016 and 2017 with historical observations from 1952,
1970, 2000, and 2011. In just the summer of 2017, we observed coastal retreat
of 14.5 m, more than 6 times faster than the long-term average rate of
2.2±0.1 m a−1 (1952–2017). Coastline retreat rates exceeded
1.0±0.1 m d−1 over a single 4 d period. Over 40 d, we estimated
removal of ca. 0.96 m3 m−1 d−1. These findings highlight
the episodic nature of shoreline change and the important role of storm
events, which are poorly understood along permafrost coastlines. We found
drone surveys combined with image-based modelling yield fine spatial
resolution and accurately geolocated observations that are highly suitable to
observe intra-seasonal erosion dynamics in rapidly changing Arctic
landscapes.
Assessment of shoreline changes for setback zone establishment from Son Tra (Da Nang city) to Cua Dai (Hoi An city), Vietnam