James, AD orcid.org/0000-0003-0532-0065, Moon, DR, Feng, W orcid.org/0000-0002-9907-9120 et al. (4 more authors) (2017) The Uptake of HO₂ on Meteoric Smoke Analogues. Journal of Geophysical Research: Atmospheres, 122 (1). pp. 554-565. ISSN 2169-897X
Abstract
The kinetics of heterogeneous HO2 uptake onto Meteoric Smoke Particles (MSPs) has been studied in the laboratory using analogues of MSP aerosol entrained into a flow tube. The uptake coefficient, y, was determined on synthetic amorphous olivine (MgFeSiO4) to be (6.9 ± 1.2) × 10‐2 at a relative humidity (RH) of 10%. On forsterite (Mg2SiO4), y = (4.3 ± 0.4) × 10‐3 at RH = 11.6%, and (7.3 ± 0.4) × 10‐2 at RH = 9.9% on fayalite (Fe2SiO4). These results indicate that Fe plays a more important mechanistic role than Mg in the removal of HO2 from the gas phase. Electronic structure calculations show that Fe atoms exposed at the particle surface provide a catalytic site where HO2 is converted to H2O2 via an Eley‐Rideal mechanism, but this does not occur on exposed surface Mg atoms. The impact of this heterogeneous process in the middle atmosphere was then investigated using a whole atmosphere chemistry‐climate model which incorporates a microphysical treatment of MSPs. Using a global MSP production rate from meteoric ablation of 44 tons per day, heterogeneous uptake (with y = 0.2) on MSPs significantly alters the HOx budget in the night‐time polar vortex. This impact is highly latitude dependent and thus could not be confirmed using currently available satellite measurements of HO2, which are largely unavailable at latitudes greater than 70°.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | © 2016. American Geophysical Union. All Rights Reserved. An edited version of this paper was published by AGU. James, A. D., D. R. Moon, W. Feng, P. S. J. Lakey, V. L. Frankland, D. E. Heard, and J. M. C. Plane (2017), The uptake of HO2 on meteoric smoke analogues, J. Geophys. Res. Atmos., 122, 554–565, doi:10.1002/2016JD025882. To view the published open abstract, go to https://doi.org/10.1002/2016JD025882. Uploaded with permission from the publisher. |
Keywords: | middle atmosphere; meteoric smoke; HO2 uptake; polar vortex; polar ozone |
Dates: |
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Institution: | The University of Leeds |
Academic Units: | The University of Leeds > Faculty of Engineering & Physical Sciences (Leeds) > School of Chemistry (Leeds) > Physical Chemistry (Leeds) |
Depositing User: | Symplectic Publications |
Date Deposited: | 17 Nov 2016 15:31 |
Last Modified: | 19 Jul 2017 10:37 |
Published Version: | https://doi.org/10.1002/2016JD025882 |
Status: | Published |
Publisher: | American Geophysical Union |
Identification Number: | 10.1002/2016JD025882 |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:107542 |