Oxidized organic molecules in the tropical free troposphere over Amazonia
Abstract
New particle formation (NPF) in the tropical free troposphere (FT) is a globally important source of cloud condensation nuclei, affecting cloud properties and climate. Oxidized organic molecules (OOMs) produced from biogenic volatile organic compounds are believed to contribute to aerosol formation in the tropical FT, but without direct chemical observations. We performed in-situ molecular-level OOMs measurements at the Bolivian station Chacaltaya at 5240 meters above sea level, on the western edge of Amazonia. For the first time, we demonstrate the presence of OOMs, mainly with 4-5 carbon atoms, simultaneously in both gas and particulate phases in tropical FT air from Amazonia. These observations, combined with air mass history analyses, indicate that the observed OOMs are linked to isoprene emitted from the rainforests hundreds of kilometers away. Based on particle-phase measurements, we find that these compounds can contribute to the growth of newly formed particles, and are potentially crucial for new particle formation in the tropical free troposphere on a continental scale. Our study will thus improve the understanding of aerosol formation process in the tropics.
Keywords
Cite
@article{arxiv.2302.14054,
title = {Oxidized organic molecules in the tropical free troposphere over Amazonia},
author = {Qiaozhi Zha and Diego Aliaga and Radovan Krejci and Victoria Sinclair and Cheng Wu and Wiebke Scholz and Liine Heikkinen and Eva Partoll and Yvette Gramlich and Wei Huang and Markus Leiminger and Joonas Enroth and Otso Peräkylä and Runlong Cai and Xuemeng Chen and Alkuin Maximilian Koenig and Fernando Velarde and Isabel Moreno and Tuukka Petäjä and Paulo Artaxo and Paolo Laj and Armin Hansel and Samara Carbone and Markku Kulmala and Marcos Andrade and Douglas Worsnop and Claudia Mohr and Federico Bianchi},
journal= {arXiv preprint arXiv:2302.14054},
year = {2023}
}