Earth’s Cryosphere, 2017, Vol. XXI, No. 1, p. 32-40
MODELING OF COASTAL DYNAMICS OF THE LAPTEV AND EAST SIBERIAN SEAS IN THE SECOND HALF OF THE HOLOCENE
S.O. Razumov, M.N. Grigoriev
Melnikov Permafrost Institute, SB RAS,
36, Merzlotnaya str., Yakutsk, 677010, Russia; razum55@mail.ru, grigoriev@mpi.ysn.ru
Two mathematical models of the Laptev and East Siberian seas coastal dynamics – multifactor model and multiplicative phenomenological model – have been developed and used for evaluation of their coastal retreat rate during the Holocene. Thermo-erosion affecting their ice-rich coasts occurred most intensely during the Subboreal period (from 10 to 20 m/year) in the Holocene and in the Early Middle Ages (8–15 m/year). Average rate of the east Siberian seas coastline retreat caused by coastal permafrost degradation ranged for the most part between 2 and 6 m/year over 500 years BP. However, it has drastically increased to 8–19 m/year in the last 40 years. Modern climatic conditions and retreat rates of the ice-rich coasts are found to be close to those existing during the Atlantic and Subboreal optimums of the second half of Holocene, when the mean air temperature anomalies reached 2 °C and more during thawing season (July through September), in the absence of multiyear ice in the Siberian seas.
Coastal dynamics, mathematical modeling, multifactor and multiplicative models, average air temperature in thawing season, multiyear sea ice