This paper explore the role of snow cover for the land–atmosphere exchange of CO2 and water vapor in alpine tundra ecosystems at the Finse site in alpine Norway (1210 m a.s.l.). Pirk et al. combined 3 years (2019–2021) of continuous flux measurements of the net ecosystem exchange of CO2 (NEE) and evapotranspiration (ET) with a ground-based ecosystem-type classification and satellite imagery. While the snow conditions in 2019 and 2021 can be described as site typical, 2020 features an extreme snow accumulation causing a 1-month delay in melt-out date, reducing 1) the total annual ET by 50 % compared to 2019 and 2021, and 2) the growing-season carbon assimilation to turn the ecosystem from a moderate annual carbon sink to a source. These results underpin the strong dependence of ecosystem structure and functioning on snow dynamics, whose anomalies can result in important ecological extreme events for alpine ecosystems.
The article can be read at the journal website.
Pirk, N., Aalstad, K., Yilmaz, Y.A., Vatne, A., Popp, A.L., Horvath, P., Bryn, A., Vollsnes, A.V., Westermann, S., Berntsen, T.K., Stordal, F., Tallaksen, L.M., 2023. Snow–vegetation–atmosphere interactions in alpine tundra. Biogeosciences 20, 2031–2047. https://doi.org/10.5194/bg-20-2031-2023