Frequent rainfall-induced new particle formation within the canopy in the Amazon rainforest
Abstract Atmospheric aerosol particles are essential for forming clouds and precipitation, thereby influencing Earth’s energy budget, water cycle and climate on regional and global scales. However, the origin of aerosol particles over the Amazon rainforest during the wet season is poorly understood. Earlier studies showed new particle formation in the outflow of deep convective clouds and suggested a downward flux of aerosol particles during precipitation events. Here we use comprehensive aerosol, trace gas and meteorological data from the Amazon Tall Tower Observatory to show that rainfall regularly induces bursts of nanoparticles in the nucleation size range. This can be attributed to rain-related scavenging of larger particles and a corresponding reduction of the condensation sink, along with an ozone injection into the forest canopy, which could increase the oxidation of biogenic volatile organic compounds, especially terpenes, and enhance new particle formation. During and after rainfall, the nucleation particle concentrations directly above the canopy are greater than those higher up. This gradient persists throughout the wet season for the nucleation size range, indicating continuous particle formation within the canopy, a net upward flux of newly formed particles and a paradigm shift in understanding aerosol–cloud–precipitation interactions in the Amazon. Particle bursts provide a plausible explanation for the formation of cloud condensation nuclei, leading to the local formation of green-ocean clouds and precipitation. Our findings suggest that an interplay of a rain-related reduction in the condensation sink, primary emissions of gases, mainly terpenes, and particles from the forest canopy, and convective cloud processing determines the population of cloud condensation nuclei in pristine rainforest air.
Authors
- Susan Trumbore (ORCID: https://orcid.org/0000-0003-3885-6202)
- Bruna A. Holanda (ORCID: https://orcid.org/0000-0003-3444-0912)
- Stefan Wolff (ORCID: https://orcid.org/0000-0003-0103-4889)
- Micael A. Cecchini (ORCID: https://orcid.org/0000-0002-0219-2857)
- Achim Edtbauer (ORCID: https://orcid.org/0000-0001-8824-2132)
- Bruno B. Meller (ORCID: https://orcid.org/0000-0002-3511-3940)
- Leslie A. Kremper (ORCID: https://orcid.org/0000-0002-8333-3059)
- Radovan Krejčí (ORCID: https://orcid.org/0000-0002-9384-9702)
- Hartwig Harder (ORCID: https://orcid.org/0000-0002-6868-714X)
- Mira L. Pöhlker (ORCID: https://orcid.org/0000-0001-6852-0756)
- Stefanie Hildmann (ORCID: https://orcid.org/0000-0002-9844-9556)
- Jonathan Williams (ORCID: https://orcid.org/0000-0001-9421-1703)
- Jos Lelieveld (ORCID: https://orcid.org/0000-0001-6307-3846)
- Joachim Curtius (ORCID: https://orcid.org/0000-0003-3153-4630)
- Paulo Eduardo Artaxo (ORCID: https://orcid.org/0000-0001-7754-3036)
- Ilona Riipinen (ORCID: https://orcid.org/0000-0001-9085-2319)
- Luiz A. T. Machado (ORCID: https://orcid.org/0000-0002-8243-1706)
- Sebastian Brill (ORCID: https://orcid.org/0000-0002-8535-6182)
- Thorsten Hoffmann (ORCID: https://orcid.org/0000-0003-0939-271X)
- Ulrich Pöschl (ORCID: https://orcid.org/0000-0003-1412-3557)
- Marco A. Franco (ORCID: https://orcid.org/0000-0002-2279-7722)
- Meinrat O. Andreae (ORCID: https://orcid.org/0000-0003-1968-7925)
- Akima Ringsdorf (ORCID: https://orcid.org/0000-0002-1764-6516)
- Yafang Cheng (ORCID: https://orcid.org/0000-0003-4912-9879)
- Gabriela R. Unfer (ORCID: https://orcid.org/0000-0001-8727-2831)
- Théodore Khadir (ORCID: https://orcid.org/0000-0003-1287-3047)
- Carlos A. Quesada
- Christopher Pöhlker (ORCID: https://orcid.org/0000-0001-6958-425X)
- Yunfan Liu
Institutions
- Goethe University Frankfurt (DE)
- Cyprus Institute (CY)
- Scripps Institution of Oceanography (US)
- Stockholm University (SE)
- Deutscher Wetterdienst (DE)
- Universidade de São Paulo (BR)
- Instituto Nacional de Pesquisas da Amazônia (BR)
- Johannes Gutenberg University Mainz (DE)
- King Saud University (SA)
- University of California San Diego (US)
- Max Planck Institute for Chemistry (DE)
- Leibniz Institute for Tropospheric Research (DE)
- Max Planck Institute for Biogeochemistry (DE)
- Bolin Centre for Climate Research (SE)
- Nanjing University (CN)
- Leipzig University (DE)
Publication Details
- Journal
- Nature Geoscience
- Published
- 2024-11-08
- DOI
- https://doi.org/10.1038/s41561-024-01585-0
- Citations
- 9
- Primary Topic
- Atmospheric chemistry and aerosols
- Type
- article
- Field-Weighted Citation Impact
- 3.39
Funders
- Fundação de Amparo à Pesquisa do Estado de São Paulo
- Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
- Bundesministerium für Bildung und Forschung
- Ministério da Ciência, Tecnologia e Inovação
- Conselho Nacional de Desenvolvimento Científico e Tecnológico
- Max-Planck-Gesellschaft
- Financiadora de Estudos e Projetos
- Fundação de Amparo à Pesquisa do Estado do Amazonas
- Instituto Nacional de Pesquisas da Amazônia
- Universidade do Estado do Amazonas