EGU2020-13853
https://doi.org/10.5194/egusphere-egu2020-13853
EGU General Assembly 2020
© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.

Precipitation isotope (δ¹⁸O, δ²H, d-excess) seasonality across the Pan-Arctic during MOSAiC

Moein Mellat1, Hannah Bailey1, Kaisa-Riikka Mustonen1, Hannu Marttila1, Pete D. Akers2, Eric S. Klein3, Jeffrey M. Welker1,3,4, and the PAPIN*
Moein Mellat et al.
  • 1University of Oulu, Oulu, Finland (moein.mellat@oulu.fi)
  • 2University of Grenoble, Grenoble, France
  • 3University of Alaska, Anchorage, USA
  • 4U-Arctic Research Chair
  • *A full list of authors appears at the end of the abstract

Stable isotopes of oxygen and hydrogen in precipitation (δ18OP, δ2HP, d-excess) are valuable hydrological tracers linked to ocean-atmospheric processes such as moisture source, storm trajectory, and seasonal temperature cycles. However, characteristics of δ18OP, δ2HP and d-excess and the processes governing them are yet to be quantified across the Arctic due to a lack of long-term empirical data. The Pan-Arctic Precipitation Isotopes Network (PAPIN) is a new coordinated network of 24 stations aimed at the direct sampling, analysis, and synthesis of precipitation isotope geochemistry in the north. Our ongoing event-based sampling provides a rich spatial dataset during the Multidisciplinary drifting Observatory for the Study of Arctic Climate (“MOSAiC”) expedition and new insight into coupled climate processes operating in the Arctic today. To date, precipitation δ18O and δ2H data (2018-2019) exhibit pronounced spatial and seasonal variability that broadly conforms to theoretical and observed understanding: (1) decreasing δ18OP/ δ2HP with increasing latitude and elevation, (2) decreasing δ18OP/ δ2HP with increasing continentality, and (3) increasing δ18OP/ δ2HP with increasing SAT. However, event-based sampling reveals remarkable variability among these relationships. For example, our observed Arctic mean summer -latitude slope of -0.3‰/degree of latitude is 50% smaller than the annual latitude effect in the mid-latitudes (-0.6‰/degree). This rate decreases to -0.1‰/degree of latitude in Finland and Russia, while in Alaska and northern Canadian a -0.7‰/degree latitudinal rate is observed. Similarly, we observe marked spatial differences in mean δ18O-temperature coefficients. Using back-trajectory analysis, we attribute these nuances to divergent moisture sources and transport pathways into, within, and out of the Arctic, and demonstrate how atmospheric circulation processes drive changes in isotope geochemistry and climate that are linked to sea ice concentration. For example, Alaska moisture derived from the North Pacific Ocean, Sea of Okhotsk, and the Bering Sea remains relatively enriched in 18OP/2H due to higher sea surface temperatures, whereas moisture originating from ice-covered seas to the north is characterized by relatively depleted values. This is the first coordinated network to quantify the spatial patterns of isotopes in precipitation, simultaneously, across the entire Arctic. In combination with a Pan-Arctic network of continuous water vapor isotope analyzers, our process-level studies will resolve the patterns and processes governing the δ18O, δ2H and d-excess values of the Arctic water cycle during the MOSAiC expedition and beyond.

PAPIN:

Artem Chupakov (Federal Center for Integrated Arctic Research), Sergey Vorobyev & Sergey Loiko & Sergey Kirpotin & Rinat Manasypov (Tomsk State University), Evgeny Zarov & Iliya Filippov (Yugra state university), Katrine Raundrup & Maia Olsen & Ida Bomholt & Dyrholm Jacobsen (Greenland Institute of Natural Resources), Dmitry Divine & colleagues (Ny-Ålesund Research Station), Anne Morgenstern & Hanno Meyer (Alfred Wegener Institute), Giles Gauthier (Laval University), Georgy Shtro (PAE UB RAS), Sergey Serikov (SB RAS), Konstantin Gribanov & Olga Stukova (Ural Federal University), Sölvi Rúnar Vignisson (Sudurnes Science and Learning Center), Samantha Jones & Brent Else & Patrik Duke (University of Calgary), (Polar Knowledge Canada), Morten Rasch & Aart Kroon (University of Copenhagen), Syndonia Bret-Harte (University of Alaska), Otso Suominen, Ilkka Syvänperä (University of Turku), Valtteri Hyöky (Parks & Wildlife Finland), Riku Paavola (University of Oulu), Torbjørn Håkan Ergon & John Burkhard (University of Oslo)

How to cite: Mellat, M., Bailey, H., Mustonen, K.-R., Marttila, H., Akers, P. D., Klein, E. S., and Welker, J. M. and the PAPIN: Precipitation isotope (δ¹⁸O, δ²H, d-excess) seasonality across the Pan-Arctic during MOSAiC, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-13853, https://doi.org/10.5194/egusphere-egu2020-13853, 2020

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