EGU23-4499, updated on 22 Feb 2023
EGU General Assembly 2023
© Author(s) 2023. This work is distributed under
the Creative Commons Attribution 4.0 License.

Top-down constraint of net carbon exchange in tropical South America

Santiago Botía1, Saqr Munassar1, Thomas Koch1, Amir Hossein Abdi1, Luana S. Basso1, Shujiro Komiya2, Jost Lavric3, David Walter4, Luciana V. Gatti5, Emanuel Gloor8, John Miller6, Wouter Peters7, Christian Rödenbeck1, and Christoph Gerbig1
Santiago Botía et al.
  • 1Max Planck Institute for Biogeochemistry, Biogeochemical Signals, Jena, Germany
  • 2Max Planck Institute for Biogeochemistry, Biogeochemical Processes, Jena, Germany
  • 3ACOEM, Australasia, Jena, Germany
  • 4Max Planck Institute for Chemistry, Multiphase Chemistry Department, Mainz, Germany
  • 5National Institute for Space Research (INPE), São José dos Campos, Brazil
  • 6Global Monitoring Laboratory, National Oceanic and Atmospheric Administration (NOAA), Boulder, USA
  • 7Wageningen University, Wageningen, The Netherlands
  • 8School of Geography, University of Leeds, Leeds, United Kingdom

The contribution of vegetation to the South American carbon balance is critical for understanding the regional dynamics in net carbon exchange. Of particular interest is the role of the Amazon region as a sink or source of carbon to the atmosphere. Recent evidence indicate a weakening of the Amazon carbon sink, and when taking fires into account, the region represents a source of carbon to the atmosphere. In this study we use a regional atmospheric inversion system together with data from the Amazon Tall Tower Observatory (ATTO) and airborne profiles of CO2, to constrain the Net Biome Exchange (NBE) in tropical South America. At the domain-wide scale we find that the atmospheric observations can constrain 64% of the land mass, with uncertainty reductions in most of the Amazon region, and the adjacent Cerrado and Caatinga biomes. Furthermore, we provide a sub-regional-specific analysis showing the effect of assimilating the Amazon Tall Tower Observatory CO2 time series on the mean seasonal cycle of NBE for four areas within the Amazon, the Cerrado and the Caatinga. An emerging sink-source gradient between the Amazon region (sink) and the integrated effect of the Cerrado and Caatinga (source) is found, but the source is located in the boundaries and outside the eastern border of the legal Amazon. Optimized NBE estimates at regional and subregional scales are shown and the importance of the continuous measurements at ATTO is highlighted. Finally, we indicate the areas with a limited data constraint in our system and conclude that the observational network has to be further expanded for reducing the remaining uncertainty in top-down inverse approaches for this region.

How to cite: Botía, S., Munassar, S., Koch, T., Abdi, A. H., Basso, L. S., Komiya, S., Lavric, J., Walter, D., Gatti, L. V., Gloor, E., Miller, J., Peters, W., Rödenbeck, C., and Gerbig, C.: Top-down constraint of net carbon exchange in tropical South America, EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-4499,, 2023.