Surface ozone in the Southern Hemisphere : 20 years of data from a site with a unique setting in El Tololo, Chile

Anet, Julien G.; Steinbacher, Martin; Gallardo, Laura; Velásquez Álvarez, Patricio A.; Emmenegger, Lukas; Buchmann, Brigitte

doi:10.21256/zhaw-4649

Please use this identifier to cite or link to this item: https://doi.org/10.21256/zhaw-4649

Publication type:	Article in scientific journal
Type of review:	Peer review (publication)
Title:	Surface ozone in the Southern Hemisphere : 20 years of data from a site with a unique setting in El Tololo, Chile
Authors:	Anet, Julien G. Steinbacher, Martin Gallardo, Laura Velásquez Álvarez, Patricio A. Emmenegger, Lukas Buchmann, Brigitte
DOI:	10.21256/zhaw-4649 10.5194/acp-17-6477-2017
Published in:	Atmospheric Chemistry and Physics
Volume(Issue):	17
Issue:	10
Page(s):	6477
Pages to:	6492
Issue Date:	2017
Publisher / Ed. Institution:	Copernicus
ISSN:	1680-7316 1680-7324
Language:	English
Subject (DDC):	551: Geology and hydrology
Abstract:	The knowledge of surface ozone mole fractions and their global distribution is of utmost importance due to the impact of ozone on human health and ecosystems and the central role of ozone in controlling the oxidation capacity of the troposphere. The availability of long-term ozone records is far better in the Northern than in the Southern Hemisphere, and recent analyses of the seven accessible records in the Southern Hemisphere have shown inconclusive trends. Since late 1995, surface ozone is measured in situ at "El Tololo", a high-altitude (2200ma.s.l.) and pristine station in Chile (30°S, 71°W). The dataset has been recently fully quality controlled and reprocessed. This study presents the observed ozone trends and annual cycles and identifies key processes driving these patterns. From 1995 to 2010, an overall positive trend of ∼ 0.7ppb decade−1 is found. Strongest trends per season are observed in March and April. Highest mole fractions are observed in late spring (October) and show a strong correlation with ozone transported from the stratosphere down into the troposphere, as simulated with a model. Over the 20 years of observations, the springtime ozone maximum has shifted to earlier times in the year, which, again, is strongly correlated with a temporal shift in the occurrence of the maximum of simulated stratospheric ozone transport at the site. We conclude that background ozone at El Tololo is mainly driven by stratospheric intrusions rather than photochemical production from anthropogenic and biogenic precursors. The major footprint of the sampled air masses is located over the Pacific Ocean. Therefore, due to the negligible influence of local processes, the ozone record also allows studying the influence of El Niño and La Niña episodes on background ozone levels in South America. In agreement with previous studies, we find that, during La Niña conditions, ozone mole fractions reach higher levels than during El Niño conditions.
URI:	https://digitalcollection.zhaw.ch/handle/11475/8898
Fulltext version:	Published version
License (according to publishing contract):	CC BY 3.0: Attribution 3.0 Unported
Departement:	School of Engineering
Organisational Unit:	Centre for Aviation (ZAV)
Appears in collections:	Publikationen School of Engineering

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Anet, J. G., Steinbacher, M., Gallardo, L., Velásquez Álvarez, P. A., Emmenegger, L., & Buchmann, B. (2017). Surface ozone in the Southern Hemisphere : 20 years of data from a site with a unique setting in El Tololo, Chile. Atmospheric Chemistry and Physics, 17(10), 6477–6492. https://doi.org/10.21256/zhaw-4649

Anet, J.G. et al. (2017) ‘Surface ozone in the Southern Hemisphere : 20 years of data from a site with a unique setting in El Tololo, Chile’, Atmospheric Chemistry and Physics, 17(10), pp. 6477–6492. Available at: https://doi.org/10.21256/zhaw-4649.

J. G. Anet, M. Steinbacher, L. Gallardo, P. A. Velásquez Álvarez, L. Emmenegger, and B. Buchmann, “Surface ozone in the Southern Hemisphere : 20 years of data from a site with a unique setting in El Tololo, Chile,” Atmospheric Chemistry and Physics, vol. 17, no. 10, pp. 6477–6492, 2017, doi: 10.21256/zhaw-4649.

ANET, Julien G., Martin STEINBACHER, Laura GALLARDO, Patricio A. VELÁSQUEZ ÁLVAREZ, Lukas EMMENEGGER und Brigitte BUCHMANN, 2017. Surface ozone in the Southern Hemisphere : 20 years of data from a site with a unique setting in El Tololo, Chile. Atmospheric Chemistry and Physics. 2017. Bd. 17, Nr. 10, S. 6477–6492. DOI 10.21256/zhaw-4649

Anet, Julien G., Martin Steinbacher, Laura Gallardo, Patricio A. Velásquez Álvarez, Lukas Emmenegger, and Brigitte Buchmann. 2017. “Surface Ozone in the Southern Hemisphere : 20 Years of Data from a Site with a Unique Setting in El Tololo, Chile.” Atmospheric Chemistry and Physics 17 (10): 6477–92. https://doi.org/10.21256/zhaw-4649.

Anet, Julien G., et al. “Surface Ozone in the Southern Hemisphere : 20 Years of Data from a Site with a Unique Setting in El Tololo, Chile.” Atmospheric Chemistry and Physics, vol. 17, no. 10, 2017, pp. 6477–92, https://doi.org/10.21256/zhaw-4649.