Towards a physics-based parameterization of pan-Arctic shoreline erosion

Abstract:

The erosion of Arctic coastlines and lake shorelines is causing problems with indigenous, industrial, military infrastructure. Large amounts of carbon previously stored in soils is constantly being released into water bodies, causing changes in local biogeochemistry. Erosion and its associated consequences are not captured by global climate models, which restricts our ability to predict and prepare for such changes in our climate system. There has been extensive work on local erosion modeling efforts, but they involve site-specific processes and are validated by unique coastlines or conditions which are too complex to be incorporated into larger earth system models. For the first time, we present a simple process-based model that aims to capture circum-Arctic erosion rates with the intention for future implementation in climate models. The model uses heat and sediment volume balances in order to predict horizontal cliff retreat and vertical erosion of a fronting beach, and is coupled to a storm surge model forced with reanalysis winds. We provide a proof-of-concept using two validation sites with observed erosion rates, one along the southern Beaufort Sea coastline, and the other along the Siberian Laptev Sea. Although this model has been applied to arctic coastlines, future application is possible to the more extensive cumulative perimeter of arctic lakes.