A Probabilistic Model of Coastal Bluff-Top Erosion in High Latitudes Due to Thermoabrasion: A Case Study from Baydaratskaya Bay in the Kara Sea

Abstract

Arctic coastal erosion demands more attention as the global climate continues to change. Unlike those along low-latitude and mid-latitude, sediments along Arctic coastlines are often frozen, even during summer. Thermal and mechanical factors must be considered together when analysing Arctic coastal erosion. Two major erosion mechanisms in the Arctic have been identified: thermodenudation and thermoabrasion. Field observations of Arctic coastal erosion are available in Baydaratskaya Bay in the Kara Sea. The objective of this study is to develop a probabilistic model of thermoabrasion to simulate the measured coastal erosion at two sites where observations suggest thermoabrasion is dominant. The model simulates two time periods: (a) the summer of 2013 (2012−2013) and (b) the summer of 2017 (2016−2017). A probabilistic analysis is performed to quantify the uncertainties in the model results. The input parameters are assumed to follow normal and lognormal distributions with a 10% coefficient of variation. Monte Carlo simulation is applied to determine the erosion rates for the two different cases. The simulation results agree reasonably well with the field observations. In addition, a sensitivity analysis is performed, revealing a very high sensitivity of the model to sea-level changes. The model indicates that the relation between sea-level rise and thermoabrasional erosion is exponential.

Keywords

• thermodenudation
• thermoabrasion
• probabilistic model
• permafrost
• storm surge
• niche growth
• bluff collapse