Dissertation abstractFree to read
Spatial features of chemical and isotopic composition of atmospheric precipitation in Uzbekistan
Ўзбекистонда атмосфера ёғинлари кимёвий ва изотоп таркибининг ҳудудий хусусиятлари
- Hydrometeorological Research Institute, Tashkent, Uzbekistan
Highlights
- Isotopes: six GNIP stations, 2022–2024 (Tashkent, Angren, Bashkizilsay, Fergana, Samarkand, Shakhrisabz); chemistry: 12 stations, 2000–2024.
- Mean δ¹⁸O and δ²H (‰): Tashkent −7.78 and −49.22; Angren −7.89 and −48.95; Bashkizilsay −9.20 and −56.26.
- Mean δ¹⁸O and δ²H (‰): Fergana −6.81 and −45.10; Samarkand −6.77 and −42.59; Shakhrisabz −6.98 and −34.71.
- Single values ranged from −19.87‰ to 2.21‰ for δ¹⁸O and from −148.10‰ to 21.60‰ for δ²H.
- Local meteoric water line for Uzbekistan: δ²H = 7.40 δ¹⁸O + 7.81.
- Precipitation chemistry: mean annual pH 6.2–7.2; mineralisation from 26.0 mg/L at Bashkizilsay to 172.4 mg/L at Almalyk.
Summary
Serik Isabekov, a junior researcher at the Hydrometeorological Research Institute, studies the chemical and isotopic composition of precipitation in Uzbekistan in this PhD thesis; its defence was set for 17 April 2026. The chemistry is based on 2000–2024 data from 12 Uzhydromet stations. The isotope part is the first systematic study of δ²H and δ¹⁸O in Uzbekistan’s precipitation: samples from six stations, Tashkent, Angren, Bashkizilsay, Fergana, Samarkand and Shakhrisabz, were collected in 2022–2024 and analysed at the IAEA laboratory. Before this, the global GNIP database held data for Uzbekistan only from the Tashkent Observatory station, for 1971.
Precipitation is mostly of the sulphate–bicarbonate–calcium type. Mean annual pH ranged from 6.2 to 7.2, with monthly lows of 4.1 at Almalyk, Fergana, Shakhrisabz and Dukant, which the author links to emissions from coal-fired power plants and industry. Mineralisation was highest at Almalyk (172.4 mg/L), Angren (147.6 mg/L) and Bekabad (125.2 mg/L), and lowest at the mountain stations Bashkizilsay (26.0 mg/L) and Dukant (36.3 mg/L).
δ¹⁸O and δ²H are lowest in winter and highest in summer, a seasonal temperature effect of the sharply continental climate. Precipitation is isotopically lightest at the mountain stations Bashkizilsay and Angren and heavier in the foothills and valleys at Shakhrisabz, Fergana and Samarkand, which the author attributes to the altitude effect.
The local meteoric water line for Uzbekistan, δ²H = 7.40 δ¹⁸O + 7.81, lies close to the global line, δ²H = 8 δ¹⁸O + 10, but with a lower slope, which the author relates to evaporation in the arid climate; points move further from the global line in the warm season. The 2022–2024 isotope data were added to the GNIP database of the WMO and the IAEA.
Figures (2)
How to cite
Serik Isabekov (2026). Spatial features of chemical and isotopic composition of atmospheric precipitation in Uzbekistan. PhD dissertation abstract in geographical sciences (11.00.03 – Land hydrology. Water resources. Hydrochemistry), Hydrometeorological Research Institute, Tashkent. https://nigmi.uz/%d0%b7%d0%b0%d1%89%d0%b8%d1%82%d0%b0-%d0%b4%d0%b8%d1%81%d1%81%d0%b5%d1%80%d1%82a%d1%86%d0%b8%d0%be%d0%bd%d0%bd%d0%be%d0%b9-%d1%80%d0%b0%d0%b1%d0%be%d1%82%d1%8b-%d0%bc%d0%bb%d0%b0%d0%b4%d1%88%d0%b5/