GC009-0013
Six years of atmospheric CO2, CH4 and CO at the Amazon Tall Tower Observatory: a new opportunity to study processes on seasonal and inter-annual scales
Monday, 7 December 2020
Poster
Santiago Botia1, Michal Galkowski1, Julia Marshall1, Thomas Koch1, Jost V. Lavric2, David Walter3, Shujiro Komiya4, Gilberto Fisch5, Wouter Peters6, Meinrat O Andreae7, Martin Heimann8 and Christoph Gerbig1, (1)Max Planck Institute for Biogeochemistry, Biogeochemical Signals, Jena, Germany, (2)Max Planck Institute for Biogeochemistry, Biogeochemical Processes Department, Jena, Germany, (3)Max Planck Institute for Chemistry, Multiphase Chemistry Department, Mainz, Germany, (4)Max Planck Institute for Biogeochemistry, Biogeochemical Processes, Jena, Germany, (5)Instituto de Aeronautica e Espaço, Departamento de Ciência e Tecnologia Aeroespacial (DCTA),, São José dos Campos, Brazil, (6)Wageningen University, Meteorology and Air Quality, Wageningen, Netherlands, (7)Max Planck Institute for Chemistry, Biogeochemistry Department, Mainz, Germany, (8)Max Planck Institute for Biogeochemistry, Biogeochemical Systems, Jena, Germany
Abstract:
The Amazon rainforest plays a crucial role in the exchange of carbon on regional and global scales. This exchange of carbon is mediated by interactions between the biosphere and the atmosphere through different atmospheric carbon species such as CO
2, CH
4 and CO. The atmospheric concentrations of these species can be linked to processes associated with sources and sinks of these gases, such as photosynthesis and respiration (CO
2), wetland emissions (CH
4) and biomass burning (CO). Atmospheric measurements at high-precision and high temporal resolution are very sparse in the Amazon, but can provide more insights into the spatial and temporal variability of such sources and sinks. In this study we present the first six years (2014-2019) of continuous and high-precision measurements of atmospheric CO
2, CH
4 and CO at the Amazon Tall Tower Observatory (ATTO, located at 2.1°S, 58.9°W, measurement level 80 m).
For CO2 and CH4, we observe a mild seasonality with a maximum in the transition from wet to dry seasons (CO2) or at the beginning of the dry season (CH4). For CO the highest values are observed at the end of the dry season, mainly driven by biomass burning in the Amazon basin. We created our own Lagrangian footprint-based simulations with the atmospheric transport model STILT, to evaluate this seasonal cycle in several gridded flux datasets when transported in the atmosphere and co-sampled with our ATTO records. For CO2 and CH4 we find that observed seasonal patterns cannot be well reproduced with out simulations, whereas for CO the timing and shape of the seasonal cycle is well captured. Such differences suggest that the underlying fluxes are the main source of error rather than the transport, likely related to an incomplete understanding of the underlying processes. We conclude that the lack of processes such as phenology (CO2), tree-mediated CH4 emissions and a more detailed wetland extent representation in the flux datasets are plausible explanations for these discrepancies. Our study highlights the importance of the ATTO measurements to provide new insights at various temporal scales.
