Simulation of Coastal Dynamics at the Kara Sea

Abstract

Aleksyutina, D.; Ogorodov, S., and Shilova O.S., 2020. Simulation of coastal dynamics at the Kara Sea. In: Malvárez, G. and Navas, F. (eds.), Global Coastal Issues of 2020. Journal of Coastal Research, Special Issue No. 95, pp. 330–335. Coconut Creek (Florida), ISSN 0749-0208.The coastal zone of the Arctic seas is characterized by high dynamics due to the presence of permafrost. In SW part of the Kara Sea the coastal cliffs are composed of frozen unlitified deposits. Massive ice beds and ice wedges are widespread on various absolute heights. In this region, the coastal erosion rates are 0.5 to 2 m·a-1. At the points where high cliffs have massive ice beds inclusions and low cliffs experience great storm events, erosion rates may rich 7-14 m·a-1. The coastal retreat rates have a lognormal distribution. In order to understand the destruction processes on the key sites, numeric simulations were performed. The model is based on the heat balance equation and the Stefan approach. Boundary conditions were set based on climatic parameters obtained according to the weather station (Marre-Sale). According to this data, two different periods can be identified: with a higher thermal action in 1995-2017, and a lower in 1973-1995. For these periods, numerical simulation of the coastal retreat was made. The physical parameters of the sediments applied for the simulations were derived from laboratory tests and literature The lithological composition varies from loamy clays and silts to gravel sands. Since thermodenudation causing erosion rate strongly depends on slope deposits removal process, different regimes of removal of the thawed layer were simulated. The crucial influence of slope cleaning mode, ice content in the soils and their reaction under climate changes on the erosion rates were demonstrated. Observed and simulated results correlate well.