Climate impact on mean annual cycle and interannual variability of CO<sub>2</sub> fluxes in European deciduous broadleaf and evergreen needleleaf forests: insights from observations and state-of-the-art data-driven and process-based models

Ullah, Asmat; Crétat, Julien; Michel, Gaïa; Mathieu, Olivier; Thevenot, Mathieu; Dara, Andrey; Granat, Robert; Wu, Zhendong; Bonnefoy-Claudet, Clément; Capelle, Julianne; Cacot, Jean; Kimball, John S.

doi:https://doi.org/10.5194/bg-22-4135-2025

Articles | Volume 22, issue 16

https://doi.org/10.5194/bg-22-4135-2025

© Author(s) 2025. This work is distributed under
the Creative Commons Attribution 4.0 License.

https://doi.org/10.5194/bg-22-4135-2025

© Author(s) 2025. This work is distributed under
the Creative Commons Attribution 4.0 License.

Articles | Volume 22, issue 16

Research article

|

26 Aug 2025

Research article |

| 26 Aug 2025

Climate impact on mean annual cycle and interannual variability of CO₂ fluxes in European deciduous broadleaf and evergreen needleleaf forests: insights from observations and state-of-the-art data-driven and process-based models

Asmat Ullah, Julien Crétat, Gaïa Michel, Olivier Mathieu, Mathieu Thevenot, Andrey Dara, Robert Granat, Zhendong Wu, Clément Bonnefoy-Claudet, Julianne Capelle, Jean Cacot, and John S. Kimball

Data sets

ERA5-Land hourly data from 1950 to present J. Mu\~{n}oz Sabater https://doi.org/10.24381/cds.e2161bac

FLUXCOM-X-BASE: Global CO$_2$ and water flux products from the FLUXCOM-X framework J. A. Nelson et al. https://doi.org/10.18160/5NZG-JMJE

SMAP L4 Global Daily 9 km EASE-Grid Carbon Net Ecosystem Exchange, (SPL4CMDL, Version 7) J. S. Kimball, A. Endsley, L. A. Jones et al. https://doi.org/10.5067/3K9F0S1Q5J2U

X-BASE: the first terrestrial carbon and water flux products from an extended data-driven scaling framework, FLUXCOM-X (https://meta.icos-cp.eu/collections/zfwf1Ak2I7OlziGDTX8Xl6_T) J. A. Nelson et al. https://doi.org/10.5194/bg-21-5079-2024

Short summary

We analyse how climate drives seasonal and interannual CO₂ flux variability in European forests using data from 19 sites and both process-based and data-driven models. The impact of climate on the CO₂ flux annual cycle is strong and quite similar across Europe. On the other hand, the impact of climate on year-to-year CO₂ flux variability depends on the region and the season, with reversed correlations between spring and summer in northern and central Europe.

Climate impact on mean annual cycle and interannual variability of CO2 fluxes in European deciduous broadleaf and evergreen needleleaf forests: insights from observations and state-of-the-art data-driven and process-based models

Data sets

Climate impact on mean annual cycle and interannual variability of CO₂ fluxes in European deciduous broadleaf and evergreen needleleaf forests: insights from observations and state-of-the-art data-driven and process-based models