Characterization of reactive oxidized nitrogen in the global upper troposphere using recent and historic commercial and research aircraft campaigns and GEOS-Chem

<p>Reactive oxidized nitrogen (NO<span class="inline-formula"><sub><i>y</i></sub></span>) in the upper troposphere (UT) influences global climate, air quality, and tropospheric oxidants, but this understanding is limited by knowledge of the relativ...

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Main Authors: N. Wei, E. A. Marais, G. Lu, R. G. Ryan, B. Sauvage
Format: Article
Language:English
Published: Copernicus Publications 2025-07-01
Series:Atmospheric Chemistry and Physics
Online Access:https://acp.copernicus.org/articles/25/7925/2025/acp-25-7925-2025.pdf
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author N. Wei
E. A. Marais
G. Lu
G. Lu
R. G. Ryan
R. G. Ryan
B. Sauvage
author_facet N. Wei
E. A. Marais
G. Lu
G. Lu
R. G. Ryan
R. G. Ryan
B. Sauvage
author_sort N. Wei
collection DOAJ
description <p>Reactive oxidized nitrogen (NO<span class="inline-formula"><sub><i>y</i></sub></span>) in the upper troposphere (UT) influences global climate, air quality, and tropospheric oxidants, but this understanding is limited by knowledge of the relative contributions of individual NO<span class="inline-formula"><sub><i>y</i></sub></span> components in this undersampled layer. Here, we use sporadic NASA DC-8 aircraft campaign observations, after screening for plumes and stratospheric influence, to characterize UT NO<span class="inline-formula"><sub><i>y</i></sub></span> composition and to evaluate current knowledge of UT NO<span class="inline-formula"><sub><i>y</i></sub></span> as simulated by the GEOS-Chem model. The use of DC-8 data follows confirmation that these intermittent data reproduce NO<span class="inline-formula"><sub><i>y</i></sub></span> seasonality from routine commercial aircraft observations (2003–2019), supporting the use of DC-8 data to characterize UT NO<span class="inline-formula"><sub><i>y</i></sub></span>. We find that peroxyacetyl nitrate (PAN) dominates UT NO<span class="inline-formula"><sub><i>y</i></sub></span> (30 %–64 % of NO<span class="inline-formula"><sub><i>y</i></sub></span>), followed by nitrogen oxides (NO<span class="inline-formula"><sub><i>x</i></sub>≡</span> NO <span class="inline-formula">+</span> NO<span class="inline-formula"><sub>2</sub></span>) (6 %–18 %), peroxynitric acid (HNO<span class="inline-formula"><sub>4</sub></span>) (6 %–13 %), and nitric acid (HNO<span class="inline-formula"><sub>3</sub></span>) (7 %–11 %). Methyl peroxy nitrate (MPN) makes an outsized contribution to NO<span class="inline-formula"><sub><i>y</i></sub></span> (14 %–24 %) over the Southeast US relative to the other regions sampled (2 %–7 %). GEOS-Chem, sampled along DC-8 flights, exhibits much weaker seasonality than the DC-8, underestimating summer and spring NO<span class="inline-formula"><sub><i>y</i></sub></span> and overestimating winter and autumn NO<span class="inline-formula"><sub><i>y</i></sub></span>. The model consistently overestimates peroxypropionyl nitrate (PPN) by <span class="inline-formula">∼</span> 10–16 pptv or 10 %–90 % and underestimates NO<span class="inline-formula"><sub>2</sub></span> by 6–36 pptv or 31 %–65 %, as the model is missing PPN photolysis. A model underestimate in MPN of at least <span class="inline-formula">∼</span> 50 pptv (13-fold) over the Southeast US results from uncertainties in processes that sustain MPN production as air ages. Our findings highlight that a greater understanding of UT NO<span class="inline-formula"><sub><i>y</i></sub></span> is critically needed to determine its role in the nitrogen cycle, air pollution, climate, and the abundance of oxidants.</p>
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spelling doaj-art-9ae3e88bbf50454c82bddef92362c7a52025-08-20T02:45:42ZengCopernicus PublicationsAtmospheric Chemistry and Physics1680-73161680-73242025-07-01257925794010.5194/acp-25-7925-2025Characterization of reactive oxidized nitrogen in the global upper troposphere using recent and historic commercial and research aircraft campaigns and GEOS-ChemN. Wei0E. A. Marais1G. Lu2G. Lu3R. G. Ryan4R. G. Ryan5B. Sauvage6Department of Geography, University College London, London, UKDepartment of Geography, University College London, London, UKDepartment of Geography, University College London, London, UKnow at: the Satellite Application Center for Ecology and Environment, Ministry of Ecology and Environment, Beijing, ChinaDepartment of Geography, University College London, London, UKnow at: School of Geography, Earth and Atmospheric Science, University of Melbourne, Melbourne, AustraliaLaboratoire d'Aérologie, Université de Toulouse, CNRS, Université Toulouse III Paul Sabatier, Toulouse, France<p>Reactive oxidized nitrogen (NO<span class="inline-formula"><sub><i>y</i></sub></span>) in the upper troposphere (UT) influences global climate, air quality, and tropospheric oxidants, but this understanding is limited by knowledge of the relative contributions of individual NO<span class="inline-formula"><sub><i>y</i></sub></span> components in this undersampled layer. Here, we use sporadic NASA DC-8 aircraft campaign observations, after screening for plumes and stratospheric influence, to characterize UT NO<span class="inline-formula"><sub><i>y</i></sub></span> composition and to evaluate current knowledge of UT NO<span class="inline-formula"><sub><i>y</i></sub></span> as simulated by the GEOS-Chem model. The use of DC-8 data follows confirmation that these intermittent data reproduce NO<span class="inline-formula"><sub><i>y</i></sub></span> seasonality from routine commercial aircraft observations (2003–2019), supporting the use of DC-8 data to characterize UT NO<span class="inline-formula"><sub><i>y</i></sub></span>. We find that peroxyacetyl nitrate (PAN) dominates UT NO<span class="inline-formula"><sub><i>y</i></sub></span> (30 %–64 % of NO<span class="inline-formula"><sub><i>y</i></sub></span>), followed by nitrogen oxides (NO<span class="inline-formula"><sub><i>x</i></sub>≡</span> NO <span class="inline-formula">+</span> NO<span class="inline-formula"><sub>2</sub></span>) (6 %–18 %), peroxynitric acid (HNO<span class="inline-formula"><sub>4</sub></span>) (6 %–13 %), and nitric acid (HNO<span class="inline-formula"><sub>3</sub></span>) (7 %–11 %). Methyl peroxy nitrate (MPN) makes an outsized contribution to NO<span class="inline-formula"><sub><i>y</i></sub></span> (14 %–24 %) over the Southeast US relative to the other regions sampled (2 %–7 %). GEOS-Chem, sampled along DC-8 flights, exhibits much weaker seasonality than the DC-8, underestimating summer and spring NO<span class="inline-formula"><sub><i>y</i></sub></span> and overestimating winter and autumn NO<span class="inline-formula"><sub><i>y</i></sub></span>. The model consistently overestimates peroxypropionyl nitrate (PPN) by <span class="inline-formula">∼</span> 10–16 pptv or 10 %–90 % and underestimates NO<span class="inline-formula"><sub>2</sub></span> by 6–36 pptv or 31 %–65 %, as the model is missing PPN photolysis. A model underestimate in MPN of at least <span class="inline-formula">∼</span> 50 pptv (13-fold) over the Southeast US results from uncertainties in processes that sustain MPN production as air ages. Our findings highlight that a greater understanding of UT NO<span class="inline-formula"><sub><i>y</i></sub></span> is critically needed to determine its role in the nitrogen cycle, air pollution, climate, and the abundance of oxidants.</p>https://acp.copernicus.org/articles/25/7925/2025/acp-25-7925-2025.pdf
spellingShingle N. Wei
E. A. Marais
G. Lu
G. Lu
R. G. Ryan
R. G. Ryan
B. Sauvage
Characterization of reactive oxidized nitrogen in the global upper troposphere using recent and historic commercial and research aircraft campaigns and GEOS-Chem
Atmospheric Chemistry and Physics
title Characterization of reactive oxidized nitrogen in the global upper troposphere using recent and historic commercial and research aircraft campaigns and GEOS-Chem
title_full Characterization of reactive oxidized nitrogen in the global upper troposphere using recent and historic commercial and research aircraft campaigns and GEOS-Chem
title_fullStr Characterization of reactive oxidized nitrogen in the global upper troposphere using recent and historic commercial and research aircraft campaigns and GEOS-Chem
title_full_unstemmed Characterization of reactive oxidized nitrogen in the global upper troposphere using recent and historic commercial and research aircraft campaigns and GEOS-Chem
title_short Characterization of reactive oxidized nitrogen in the global upper troposphere using recent and historic commercial and research aircraft campaigns and GEOS-Chem
title_sort characterization of reactive oxidized nitrogen in the global upper troposphere using recent and historic commercial and research aircraft campaigns and geos chem
url https://acp.copernicus.org/articles/25/7925/2025/acp-25-7925-2025.pdf
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