Net ozone production and its relationship to nitrogen oxides and volatile organic compounds in the marine boundary layer around the Arabian Peninsula

Net ozone production and its relationship to nitrogen oxides and volatile organic compounds in the marine boundary layer around the Arabian Peninsula

<p>Strongly enhanced tropospheric ozone (<span class="inline-formula">O<sub>3</sub></span>) mixing ratios have been reported in the Arabian Basin, a region with intense solar radiation and high concentrations of <span class="inline-formula">O&l...

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Bibliographic Details
Main Authors: I. Tadic, J. N. Crowley, D. Dienhart, P. Eger, H. Harder, B. Hottmann, M. Martinez, U. Parchatka, J.-D. Paris, A. Pozzer, R. Rohloff, J. Schuladen, J. Shenolikar, S. Tauer, J. Lelieveld, H. Fischer
Format: Article
Language:English
Published: Copernicus Publications 2020-06-01
Series:Atmospheric Chemistry and Physics
Online Access:https://www.atmos-chem-phys.net/20/6769/2020/acp-20-6769-2020.pdf
Description
Summary:<p>Strongly enhanced tropospheric ozone (<span class="inline-formula">O<sub>3</sub></span>) mixing ratios have been reported in the Arabian Basin, a region with intense solar radiation and high concentrations of <span class="inline-formula">O<sub>3</sub></span> precursors such as nitrogen oxides (<span class="inline-formula">NO<sub><i>x</i></sub></span>) and volatile organic compounds (VOCs). To analyze photochemical <span class="inline-formula">O<sub>3</sub></span> production in the marine boundary layer (MBL) around the Arabian Peninsula, we use shipborne observations of NO, <span class="inline-formula">NO<sub>2</sub></span>, <span class="inline-formula">O<sub>3</sub></span>, OH, <span class="inline-formula">HO<sub>2</sub></span>, HCHO, the actinic flux, water vapor, pressure and temperature obtained during the summer 2017 Air Quality and Climate in the Arabian Basin (AQABA) campaign, and we compare them to simulation results from the ECHAM-MESSy Atmospheric Chemistry (EMAC) general circulation model. Net <span class="inline-formula">O<sub>3</sub></span> production rates (NOPRs) were greatest over both the Gulf of Oman and the northern Red Sea (16&thinsp;ppbv&thinsp;d<span class="inline-formula"><sup>−1</sup></span>) and over the Arabian Gulf (32&thinsp;ppbv&thinsp;d<span class="inline-formula"><sup>−1</sup></span>). The NOPR over the Mediterranean, the southern Red Sea and the Arabian Sea did not significantly deviate from zero; however, the results for the Arabian Sea indicated weak net <span class="inline-formula">O<sub>3</sub></span> production of 5&thinsp;ppbv&thinsp;d<span class="inline-formula"><sup>−1</sup></span> as well as net <span class="inline-formula">O<sub>3</sub></span> destruction over the Mediterranean and the southern Red Sea with values of <span class="inline-formula">−1</span> and <span class="inline-formula">−4</span>&thinsp;ppbv&thinsp;d<span class="inline-formula"><sup>−1</sup></span>, respectively. Constrained by <span class="inline-formula">HCHO∕NO<sub>2</sub></span> ratios, our photochemistry calculations show that net <span class="inline-formula">O<sub>3</sub></span> production in the MBL around the Arabian Peninsula mostly occurs in <span class="inline-formula">NO<sub><i>x</i></sub></span>-limited regimes with a significant share of <span class="inline-formula">O<sub>3</sub></span> production occurring in the transition regime between <span class="inline-formula">NO<sub><i>x</i></sub></span> limitation and VOC limitation over the Mediterranean and more significantly over the northern Red Sea and Oman Gulf.</p>
ISSN:1680-7316
1680-7324

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