The importance of alkyl nitrates and sea ice emissions to atmospheric NO x sources and cycling in the summertime Southern Ocean marine boundary layer

• Published in: Atmospheric Chemistry and Physics
• Main Authors: J. M. Burger, J. Granger, E. Joyce, M. G. Hastings, K. A. M. Spence, K. E. Altieri
• Format: Article in Journal/Newspaper
• Language: English
• Published: Copernicus Publications 2022
• Subjects: Physics; QC1-999; Chemistry; QD1-999; Southern Ocean; Weddell Sea; Weddell; Sea ice
• Online Access: https://doi.org/10.5194/acp-22-1081-2022; https://doaj.org/article/8a6e5fead1a846969afc6061ea1d0d5d

Atmospheric nitrate originates from the oxidation of nitrogen oxides <math xmlns="http://www.w3.org/1998/Math/MathML" id="M3" display="inline" overflow="scroll" dspmath="mathml"><mrow><mo>(</mo><mrow class="chem"><msub><mi mathvariant="normal">NO</mi><mi>x</mi></msub></mrow><mo>=</mo><mrow class="chem"><mi mathvariant="normal">NO</mi></mrow><mo>+</mo><mrow class="chem"><msub><mi mathvariant="normal">NO</mi><mn mathvariant="normal">2</mn></msub></mrow><mo>)</mo></mrow></math> <svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="93pt" height="13pt" class="svg-formula" dspmath="mathimg" md5hash="5750f2f575feb9c155d643b1c38773c6"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="acp-22-1081-2022-ie00001.svg" width="93pt" height="13pt" src="acp-22-1081-2022-ie00001.png"/></svg:svg> and impacts both tropospheric chemistry and climate. NO x sources, cycling and NO x to nitrate formation pathways are poorly constrained in remote marine regions, especially the Southern Ocean, where pristine conditions serve as a useful proxy for the pre-industrial atmosphere. Here, we measured the isotopic composition ( δ 15 N and δ 18 O ) of atmospheric nitrate in coarse-mode ( >1 µm ) aerosols collected in the summertime marine boundary layer of the Atlantic Southern Ocean from 34.5 to 70 ∘ S and across the northern edge of the Weddell Sea. The δ 15 N – <math xmlns="http://www.w3.org/1998/Math/MathML" id="M12" display="inline" overflow="scroll" dspmath="mathml"><mrow class="chem"><msubsup><mi mathvariant="normal">NO</mi><mn mathvariant="normal">3</mn><mo>-</mo></msubsup></mrow></math> <svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="25pt" height="16pt" class="svg-formula" dspmath="mathimg" ...