Researchers model the terrestrial carbon cycle with the help of remote sensing observations
Instruments on the Sodankylä flux tower are used to study the exchange of carbon dioxide between the atmosphere and the forest. Photo: Aleksi Rimali.The study investigated how plants absorb carbon dioxide from the atmosphere and how these processes change over time, for example to climate change and environmental pollution. The modelling work will also help to understand the nitrogen and phosphorus cycles, which are important for plant growth and carbon uptake.
Better modelling and prediction of carbon uptake by natural ecosystems can help us to better assess the impact of climate policies and the role of nature in mitigating climate change.
Simple but efficient D&B model was developed using a wide range of data
The first study developed a new D&B model describing soil and terrestrial vegetation. The model has a simple structure, but can describe the plant water use and carbon uptake at both local and global scales.
The model development combined several different data sources: remote sensing observations from the satellites and field observations from Sodankylä and the Spanish savannah site. These helped to provide a diverse perspective on ecosystem functioning in different environments.
This development work was part of the Land Carbon Constellation project funded by the European Space Agency. The work brought together experts in field observations, remote sensing and modelling in a unique way.
20 years of measurements used in model development
Another study used data from a Canadian deciduous forest spanning over 20 years using the QUINCY model, which includes also nitrogen and phosphorus cycles in addition to the carbon cycle. The model includes parameterisation for leaf chlorophyll, which can also be observed from satellites.
The study found that the strength of the forest’s carbon sink has increased over time, even though the length of the growing season has not changed. This suggests that the summer photosynthesis, i.e. the uptake of carbon by the vegetation, has increased. The QUINCY model was not able to successfully simulate this behaviour, suggesting that that the explanation would be a process not included in the model. For this forest, the explanation could be recovery of nitrogen and sulphur deposition.
The study was part of Academy fellowship project of senior scientist Tea Thum, funded by the Research Council of Finland.
Further information
Senior scientist Tea Thum, Finnish Meteorological Institute, tel. +358 50 592 7359, tea.thum@fmi.fi
References for the scientific articles:
Knorr, W., Williams, M., Thum, T., Kaminski, T., Voßbeck, M., Scholze, M., Quaife, T., Smallman, T. L., Steele-Dunne, S. C., Vreugdenhil, M., Green, T., Zaehle, S., Aurela, M., Bouvet, A., Bueechi, E., Dorigo, W., El-Madany, T. S., Migliavacca, M., Honkanen, M., Kerr, Y. H., Kontu, A., Lemmetyinen, J., Lindqvist, H., Mialon, A., Miinalainen, T., Pique, G., Ojasalo, A., Quegan, S., Rayner, P. J., Reyes-Muñoz, P., Rodríguez-Fernández, N., Schwank, M., Verrelst, J., Zhu, S., Schüttemeyer, D., and Drusch, M.: A comprehensive land-surface vegetation model for multi-stream data assimilation, D&B v1.0, Geosci. Model Dev., 18, 2137–2159, https://doi.org/10.5194/gmd-18-2137-2025, 2025.
Thum, T., Miinalainen, T., Seppälä, O., Croft, H., Rogers, C., Staebler, R., Caldararu, S., and Zaehle, S.: Modelling decadal trends and the impact of extreme events on carbon fluxes in a temperate deciduous forest using a terrestrial biosphere model, Biogeosciences, 22, 1781–1807, https://doi.org/10.5194/bg-22-1781-2025, 2025.