Beyond traditional summer air temperature signals in subarctic tree rings using hydrogen and oxygen isotopes
- 1Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Zürcherstrasse 111 CH-8903 Birmensdorf, Switzerland
- 2Department of Geography, Geomatics and Environment, University of Toronto Mississauga, 3359 Mississauga Road, Mississauga, ON, L5L 1C6 Canada
- 3Siberian Federal University, 660041 Svobodny 79, Krasnoyarsk, Russian Federation
- 4Sukachev Institute of Forest SB RAS, Akademgorodok 50/28, 660036 Krasnoyarsk, Russian Federation
- 5Science Department, National Park “Krasnoyarsk Stolby”, 660006 Krasnoyarsk, Russian Federation
- 6École Polytechnique Fédérale de Lausanne EPFL, Limnology center, 1015 Lausanne, Switzerland
- 7Reshetnev Siberian State University of Science and Technology, Krasnoyarsky Rabochy 31, 660037 Krasnoyarsk, Russian Federation
- 8Kasan Federal University, Institute of geology and Petroleum Technology, Kremlyovskaya str. 18, Kazan, 420008, Russian Federation
Classical tree-ring parameters like tree-ring width, maximum latewood density and cell wall thickness record summer air temperature at high latitudes well and allow for the reconstruction of summer temperature over centuries and millennia. However, information about other climatic factors (e.g. moisture and sunshine duration) is limited in these proxies, especially for temperature-limited environments in subarctic forests growing on permafrost soils. The application of stable hydrogen and oxygen isotopes can provide complementary information about moisture changes and solar irradiation.
Solar irradiation and its seasonal distribution play an important role for trees in terms of photosynthesis and carbohydrate production, which can influence deuterium variations in organic matter in addition to hydrological processes. We found that hydrogen and oxygen isotopes in larch tree-ring cellulose from Siberia show a strong link with summer sunshine duration during the growth season. Negative correlations with sunshine duration during autumn of the previous year and winter of the current year can be related to the lack of light during polar nights at subarctic sites (> 60º N) and lack of needles in larch trees to produce photosynthates in a cold environment. Indirect effects might also arise as a high amount of winter sunshine means persistent high-pressure systems with low precipitation, therefore negatively affecting snow accumulation, which is an important water source after snow melt.
Uptake of winter precipitation is possible in the warming spring and summer months after snowmelt and thawing of the active soil layer, resulting in significant correlations between tree-ring oxygen values and winter-spring air temperatures. Oxygen isotopes in organic matter are influenced by variations in the isotopic composition of source water, which is closely related to that of precipitation and soil water (though modified by evaporation at the soil surface).
Furthermore, we observed that summer vapor pressure deficit is positively and significantly recorded in stable oxygen isotopes from northeastern Siberia, while continuously represented through spring-summer months in western Canada. Hydrogen tree-ring isotopes from the Canadian subarctic recorded a negative significant correlation with summer relative humidity, opposite to northeastern Siberia.
The application of dual hydrogen and oxygen stable isotopes in tree rings can expand our knowledge beyond traditional summer air temperature reconstructions and will help to improve climate reconstructions over the past millennia.
Acknowledgements: This work was supported by the project RSF 21-17-00006.
How to cite: Fonti, M., Saurer, M., Porter, T., Zharkov, M., Barinov, V., Taynik, A., Kirdyanov, A., Knorre, A., Wegmann, M., Trushkina, T., Koshurnikova, N., Vaganov, E., Myglan, V., Siegwolf, R., and Churakova (Sidorova), O.: Beyond traditional summer air temperature signals in subarctic tree rings using hydrogen and oxygen isotopes, EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-11722, https://doi.org/10.5194/egusphere-egu23-11722, 2023.
