Earth’s Cryosphere, 2022, Vol. XXVI, No. 4, p. 16-31.
REGIONAL AND HISTORICAL GEOCRYOLOGY
ORIGIN AND ISOTOPIC COMPOSITION OF PRECIPITATION AT EXTREMELY LOW TEMPERATURES IN YAKUTSK (EASTERN SIBERIA)
A.A. Galanin , M.R. Pavlova*, A.N. Vasil’eva, G.I. Shaposhnikov, N.V. Torgovkin**
Melnikov Permafrost Institute, Siberian Branch of the Russian Academy of Sciences, ul. Merzlotnaya 36, Yakutsk, 677010 Russia
*Corresponding author; e-mail: nigaer@yandex.ru
**Corresponding author; e-mail: nick1805torg@gmail.com
Isotopic (18O, D) and chemical composition of atmospheric precipitation (1–2-cm snow layer on the surface of the snow cover and crystalline hoar) that fell in December 2020–January 2021 under anticyclonic weather, extremely low temperatures (–47 to –52°C) and dense ice fogs has been studied at six sites along a 25-km profile from Yakutsk. Samples from the surface of the snow cover are characterized by the lightest compositions (d18 = –41.04 ± 5.11‰, dD = –326.43 ± 34.16‰, dexc = 1.91 ± 7.72‰) and are noticeably depleted of deuterium. From the suburbs to the center of Yakutsk, a significant weighting of the isotopic compositions (by 10‰ for d18O and 80‰ for dD), a decrease in dexc (from +10 to –6‰), and a fourfold increase in mineralization due to impurities of calcium carbonate have been found. The isotopic compositions of the samples of crystalline rime (d18O = –30.89 ± 5.62‰, dD = –285.88 ± 12.82‰, dexc = –28.79 ± 32.53‰) notably differ from the isotopic compositions of other forms of atmospheric precipitation, water, and ice in the studied region. These samples display the greatest variations in d18O (from –24‰ in Yakutsk to –37‰ at a distance of 25 km from its center), dD (from –255.4 to –285.9‰), and dexc (from –80 to +11.5‰). The isotopic and chemical compositions of the investigated precipitation indicate a significant proportion of technogenic water vapor entering the atmosphere during the combustion of hydrocarbon fuel. Based on the model of the Gaussian mixture and deuterium excess of the studied samples, it has been found that the maximum share of technogenic moisture in crystalline hoar reaches 26–32% near heat-generating stations; it decreases to 13–18% in the central part of the city and to 6.5–8.8% in the suburbs. In the surface layer of the snow cover, it reaches 5–6% in the central part of Yakutsk and decreases to 1% or less in the suburbs.
Keywords: stable isotopes of water, atmospheric precipitation, snow, crystalline hoar, ice fog, low temperatures, technogenic sources of precipitation, fractionation, Yakutsk, Eastern Siberia
Recommended citation: Galanin A.A., Pavlova M.R., Vasil’eva A.N., Shaposhnikov G.I., Torgovkin N.V., 2022. Origin and isotopic composition of precipitation at extremely low temperatures in Yakutsk (Eastern Siberia). Earth’s Cryosphere, XXVI (4), 16–31.