Coastal profile modeling along the Russian Arctic coast

Abstract: A morphodynamic model previously developed to predict the evolution of sedimentary coasts is extended to compare the effects of abrasion and thermal-abrasion processes on Arctic coasts. It is concluded that under the same storm impact, an unfrozen abrasion cliff loses almost the same sediment volume and retreats at almost the same rate as a thermal-abrasion cliff of corresponding effective height. Thermal impact itself presumably does not contribute to the volume of sediment losses significantly and only prepares the frozen material to be removed by waves and currents. Whatever the potential of thermal-abrasion determined by thermal effects, the volume of lost material would be limited mostly by the potential transport capacity of storm wave activity, as in the case of a pure abrasion. The long-term losses of sediments for both types of coast can be determined using an empirical relationship incorporating the effective height of the cliff, hce, taking into account the subsidence of soil after thawing of ice. The proposed model is employed to predict the evolution of thermal-abrasion and accretionary coasts in the central and eastern Russian Arctic where the sea-ice conditions at present are more severe. The recession of the thermal abrasion cliffs is expected to accelerate by 1.4 to 1.5 times in the second half of the 21st century. Evolution of the accretionary coasts may lead to development of natural berms protecting the coast from erosion. [Copyright &y& Elsevier]