Expedition of Limnological Institute to the Sygyktinsky Glacier (Kodar Ridge) in 2023

In July and August 2023, regular expeditionary research works on one of the largest glaciers of the Kodar Ridge - Sygyktinsky (or Preobrazhensky) glacier were continued within the State assignment “Study of transformations of the state of water bodies and watercourses of Eastern Siberia in seasonal and long-term aspects in the context of climate change, geological environment and anthropogenic loads” (0279-2021-0005) (led by A.P. Fedotov).

The glacier is located in the upper reaches of the left tributary of the Sulban River (Oleniy Rog River) and the Levaya Sygykta River at an altitude of 2260-2660 m above sea level on the border of Irkutsk Region and Transbaikal Territory. Since early July 2019, two automatic weather stations have been operating on the glacier, measuring dozens of meteorological parameters with high temporal resolution (30 minutes) at several altitudinal levels above the glacier surface and its upper 2-meter layer (with a vertical resolution of 10 cm).

The aims of the expedition were to study the seasonal dynamics of the glacier, to sample water, snow and ice for chemical and isotopic analyses and to maintain automatic weather stations. During the summer season of 2023 (July-August), we obtained unique data that enable to assess quantitatively the components of the heat balance during the glacier melting (radiation balance, turbulent heat and moisture exchange between the glacier surface and the atmosphere). To date, the length of continuous high-resolution series of meteorological observations on the glacier has reached 1514 days (4.1 years), which is the longest observations of this kind conducted on glaciers of Siberia.

The structure of the snow cover of the 2022/2023 accumulation season was studied in the snow pits on the glacier. Samples of deep ice (probably more ancient) were collected in the crevasse of Irkutsk branch of the glacier at depths of 360, 245 and 175 cm from the surface. Samples of new-fallen snow, glacial runoff and surface ice were collected at several altitudinal levels of the glacier. In addition, temperature measurements using automatic recorders (thermochrons) were carried out in the valleys of the rivers Sulban and Oleniy Rog at 4 levels (1070, 1240, 1830 and 2530 m above sea level), and river and lake water samples were taken in the Sulban River basin for hydrochemical and isotopic analyses.

The new experimental data are important for further parameterization of models of mountain glaciation dynamics in the domestic areas of Eurasia. These data enable to quantify the main factors of summer snow and ice melting under the conditions of modern climate change, to identify the sources of oceanic and continental moisture entering the glacier and to understand the processes of atmospheric moisture transformation in the region located on the border of Atlantic and Pacific influence in the interannual and seasonal cycles. Moreover, the methodology of isotope studies of water bodies will be practiced on real natural samples.