Structure and Variability of the Lena River Plume in the South-Eastern Part of the Laptev Sea

Abstract—This work is focused on structure and seasonal variability of the most freshened part of the Lena plume in the south-eastern part of the Laptev Sea, namely, at sea area adjacent to the eastern part of the Lena Delta and in the Buor-Khaya Bay. Based on in situ hydrological data, it is shown that accumulation of the freshwater discharge of the Lena River occurs in the Buor-Khaya Bay during the summer period. In autumn reduced salinity in this semi-isolated and shallow gulf remains significantly longer time than in the area adjacent to the eastern part of the Lena Delta that is not typical for large river plumes. As a result, the Buor-Khaya Bay plays a role of a reservoir of freshwater discharge during long autumn-winter period. Moreover, this gulf is a secondary source of freshened and warm water in the south-eastern part of the Laptev Sea which volume is similar to the discharge volume of the Lena River during the autumn-winter drought.