Monitoring Summertime Erosion Patterns Over an Arctic Permafrost Coast with Recent Sub-meter Resolution Microsatellite SAR Data

Abstract. Arctic coasts experience some of the highest rates of erosion in the world, particularly due to permafrost degradation resulting from the recent exacerbation of climate change. Therefore, not only have coastal defense and energy facilities been threatened, but maintenance costs for the infrastructure of cold regions have also risen. To monitor the coastal erosion pattern of the circum-Arctic, earlier studies often employ spaceborne or airborne optical multi-spectral images to depict shoreline changes, which are limited by frequent clouds and haze in Arctic regions and, thus, hamper the time-series analysis. Instead, this study aims to explore the synthetic aperture radar (SAR) images, especially the recently developed microsatellite SAR data, which provide unprecedented high-resolution at a sub-meter scale, to measure the summertime spatio-temporal dynamics of an ice-rich permafrost coast along the Beaufort Sea, Alaska. The results reveal a maximum shoreline change envelope (SCE) of 64.89 m during the three-month study period. To examine the differences between the estimations and the observations derived from the conventional Sentinel-1 data, the proposed multi-stage statistical-driven scheme is used. A statistically significant positive relationship between two depicted SCEs with the presence of heteroscedasticity is confirmed. In detail, the agreement between two SCEs increases with the magnitude of the SCE, indicating that the microsatellite SAR can depict more trivial changes in coastline positions. Founded on the results and detailed discussion on the uniqueness and limitations of current SAR sensors, the promising opportunity to utilize the blooming microsatellite SAR datasets for coastal monitoring is highlighted.