Ice-covering hydrological and hydrochemical investigations on the Lena River delta

¹ St. Petersburg State University, 199034, Universitetskaya nab., 7-9, St.Petersburg, Russia
² Northern water problems Institute, KarRC RAS, 185030 A. Nevsky aven., 50, Petrozavodsk, Russia

^* Corresponding author: umnichka@mail.ru

Abstract

The study reported here was conducted on the channels of the Lena River delta in April 2019. The water temperature, specific conductivity, dissolved oxygen, PAR fluxes, and currents were measured on the cross-sections in the Olenekskaya and Bykovskaya channels, as well as in the main channel of the Lena River near Samoilov Island using the multiparameter probes CTD-48M, CTD-90M and RBR-Concerto. An analysis of the data showed that the water in the channels of the Lena River delta in winter is well saturated with oxygen (4.9-6.3 ml/l), has a very low temperature (from -0.1°C to +0.8°C). The specific conductivity of water Lena River delta channels changed from 460 to 530 )S/cm. A thick layer of snow 0.1-0.5 m with an ice thickness of more than 1.5 m prevents the penetration of solar radiation into the subglacial layer, where the PAR fluxes does not exceed 10 µmol/m²s. Current velocities reached 20–25 cm/s in the Bykovskaya channel, in Olenekskaya channel – 5-11 cm/s, and in the main channel – 12-18 cm/s. The currents data obtained made it possible to calculate the discharge in the channels during the ice-period.