Abstract
Stable water isotopes in snowpack and snowfalls are widely used for understanding hydrological processes occurring in the seasonally snow-covered territories. The present study examines the main factors influencing changes of the initial stable water isotopes composition in the seasonal snow cover of the south of Western Siberia. Studies of the isotopic composition of snow precipitation and snow cover, as well as experiments with them, were carried out during two cold seasons of 2019–2021, and laser spectroscopy PICARRO L2130-i (WS-CRDS) was used for the determination of water isotope composition (δ18O and δD). The main changes in the isotopic composition of the snow cover layers in the studied region are associated with the existence of a vertical temperature gradient between the layers and with the penetration of soil moisture into the bottom layers in the absence of soil freezing. During the winter period, the sublimation from the top layer of snow is observed only at the moments of a sharp increase in the daily air temperature. At the end of winter, the contrast between day and night air temperatures determines the direction of the shift in the isotopic composition of the top layer of snow relative to the initial snow precipitation.
Highlights
It is not correct to directly use the isotopic composition data of the seasonal snow cover for hydrological, climatic, and ecological purposes because many researchers note that during the winter period various processes leading to changes in the initial isotopic composition of snow can occur in the layers of snowpack [27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48]
The main changes in the isotopic composition (δ18O and δD) of water in the layers of the snowpack are associated with the penetration and condensation of soil moisture in the snow layer closest to the snow-soil interface [27,34,38,40], movement and condensation of moisture inside the snowpack due to the existence of a vertical temperature and pressure gradients [33,38], partial thawing of snow layers [38,39,40], as well as vapor exchange between the upper layer of snow and the atmosphere [38,39,40]
The water isotopic composition of the snow precipitation during the cold period 2019–2020 in the studied area (Barnaul) varied from −30.3‰ to −12.0‰ for δ18O and from −235.4‰ to −90.7‰ for δD, in the cold period of 2020–2021 the spreading of the isotopic composition values was more significant and varied from −35.6‰ to −11.6‰ for δ18O and from −277.3‰ to −79.8‰ for δD
Summary
Data on the stable isotope compositions of oxygen and hydrogen in precipitation and snowpack is actively used to obtain important information about climatic, hydrological, and ecological changes in the environment [1,2,3,4,5,6,7,8,9,10,11,12,13,14], including the assessment of the transboundary transfer of atmospheric moisture falling on the studied area as precipitation, and the identification of the sources of this moisture [15,16,17,18,19,20,21,22,23,24]. It is not correct to directly use the isotopic composition data of the seasonal snow cover for hydrological, climatic, and ecological purposes because many researchers note that during the winter period various processes leading to changes in the initial isotopic composition of snow can occur in the layers of snowpack [27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48] All this must be taken into account when snowpack samples are used to assess the seasonal moisture supply and further its redistribution among the components of the water runoff in the catchment area after snow melting. Studying regional peculiarities and factors influencing changes in the snow’s initial stable water isotopes composition in the snowpack is an important task with a wide practical application
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
