EGU General Assembly 2023
© Author(s) 2023. This work is distributed under
the Creative Commons Attribution 4.0 License.

Intra- and inter-annual changes in isoprene emission from central Amazonia

Eliane Gomes Alves1, Raoni Aquino Santana, Cléo Quaresma Dias-Junior, Santiago Botía, Tyeen Taylor, Ana Maria Yáñez-Serrano, Jürgen Kesselmeier, Pedro Ivo Lembo Silveira de Assis, Giordane Martins, Rodrigo de Souza, Sergio Duvoisin Junior, Alex Guenther, Dasa Gu, Anywhere Tsokankunku, Matthias Sörgel, Bruce Nelson, Davieliton Pinto, Shujiro Komiya, Bettina Weber, Diogo Martins Rosa, and the Cybelli Barbosa*
Eliane Gomes Alves et al.
  • 1Max Planck Institute for Biogeochemistry, Biogeochemical Processes, Jena, Germany (
  • *A full list of authors appears at the end of the abstract

Isoprene emissions are a key component in biosphere-atmosphere interactions, and the most significant global source is the Amazon rainforest. However, intra- and inter-annual variations in biological and environmental factors that regulate isoprene emission from Amazonia are not well understood and, thereby, poorly represented in models. Here, with datasets covering several years of measurements at the Amazon Tall Tower Observatory (ATTO) in central Amazonia, Brazil, we (1) quantified canopy profiles of isoprene mixing ratios across seasons of normal and anomalous years and related them to the main drivers of isoprene emission – solar radiation, temperature, and leaf phenology; (2) evaluated the effect of leaf age on the magnitude of the isoprene emission factor (Es) from different tree species and scaled up to canopy with intra- and inter-annual leaf age distribution derived by a phenocam; and (3) adapted the leaf age algorithm from MEGAN with observed changes in Es across leaf ages. Our results showed that the variability in isoprene mixing ratios was higher between seasons (max. during the dry-to-wet transition seasons) than between years, with values from the extreme 2015 El-niño year not significantly higher than in normal years. In addition, model runs considering in-situ observations of canopy Es and the modification on the leaf age algorithm with leaf-level observations of Es presented considerable improvements in the simulated isoprene flux. This shows that MEGAN estimates of isoprene emission can be improved when biological processes are mechanistically incorporated into the model.  

Cybelli Barbosa:

How to cite: Gomes Alves, E., Aquino Santana, R., Quaresma Dias-Junior, C., Botía, S., Taylor, T., Yáñez-Serrano, A. M., Kesselmeier, J., Lembo Silveira de Assis, P. I., Martins, G., de Souza, R., Duvoisin Junior, S., Guenther, A., Gu, D., Tsokankunku, A., Sörgel, M., Nelson, B., Pinto, D., Komiya, S., Weber, B., and Martins Rosa, D. and the Cybelli Barbosa: Intra- and inter-annual changes in isoprene emission from central Amazonia, EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-4410,, 2023.