ИСТИНА

Climate change causes air and permafrost temperature growth, active layer thickening, and especially, shrinking sea ice in the Arctic. These shifts lead to the intensification of coastal destructive processes. Acceleration of coastal erosion in unlithified frozen sediments was detected in many high-latitude areas that may affect freshwater, sediments and carbon discharge to the arctic seas. Engineering facilities can be under threat of destruction in economically developed regions. The study presents the results of monitoring of the Bering Sea’s coastal section near Lorino settlement. Studied coast is 750-m length remnant of marine terrace. Application of archival maps, engineering surveys data, field geodetic measurements, and UAV shooting allowed covering the period of coastal dynamics up to 50 years. Quantity relationship between retreat rate of bluff edge and coastal zone parameters was analyzed; influence of thermo-abrasion and thermo-denudation on coastal destruction intensity and erosion rate of coastal deposits was assessed. Studied coast section retreat rate was increased for the last 50 years in an order: from less than 0.5 m∙a-1 in 1967-2010 to 4.2 m∙a-1 in 2010-2017. Such trend may be explained by increased wave effect on the coast. Retreat distance for study period in western part of coastal section is twice less than in eastern one: the values are 18.1 and 42.6 m respectively. Observed spatial differentiation of coastal dynamics is well explained by predominant destructive processes, coastal parameters and erodibility of the deposits, exposed to coastal erosion. Calculation of Normalized Difference Thermo-erosion Index (NDTI) revealed predominance of thermal abrasion process for western part of the coast and thermal denudation – for eastern one. Apparently, observed trend of coastal erosion acceleration will continue, that cause destruction of engineering facilities of Lorino community, first, fur farm shedders. Multi-year field investigations were supported by U.S. National Science Foundation (OPP-0352957 grant). Field studies and data analysis in 2018 were conducted in framework of RFBR research grant № 18-35-00192.