The Use of the Characteristics of Water Isotopic Composition for Assessing the Contribution of Winter and Summer Precipitation to the Upper Ob Runoff during the Open-Water Period

Abstract

The results of three-year (2020–2022) studies of stable isotopes (²H, ¹⁸O) in river water and atmospheric precipitation in the cold and warm seasons of the year were used to assess their contribution to river runoff in the lowland area of the Upper Ob. Despite the predominance of rain over snow precipitation (up to 2/3 of the annual amount), it was shown that snowmelt water contributes much to river runoff formation throughout the open-water period: from 42 to 61%, depending on the proportions of snow and rain that fell within a year.