H₂O₂ and CH₃OOH (MHP) in the Remote Atmosphere: 2. Physical and Chemical Controls
Abstract
Hydrogen peroxide (H₂O₂) and methyl hydroperoxide (MHP, CH₃OOH) serve as HOₓ (OH and HO₂ radicals) reservoirs and therefore as useful tracers of HOₓ chemistry. Both hydroperoxides were measured during the 2016–2018 Atmospheric Tomography Mission as part of a global survey of the remote troposphere over the Pacific and Atlantic Ocean basins conducted using the NASA DC-8 aircraft. To assess the relative contributions of chemical and physical processes to the global hydroperoxide budget and their impact on atmospheric oxidation potential, we compare the observations with two models, a diurnal steady-state photochemical box model and the global chemical transport model Goddard Earth Observing System (GEOS)-Chem. We find that the models systematically under-predict H₂O₂ by 5%–20% and over-predict MHP by 40%–50% relative to measurements. In the marine boundary layer, over-predictions of H₂O₂ in a photochemical box model are used to estimate H₂O₂ boundary-layer mean deposition velocities of 1.0–1.32 cm s⁻¹, depending on season; this process contributes to up to 5%–10% of HOₓ loss in this region. In the upper troposphere and lower stratosphere, MHP is under-predicted and H₂O₂ is over-predicted by a factor of 2–3 on average. The differences between the observations and predictions are associated with recent convection: MHP is under-estimated and H₂O₂ is over-estimated in air parcels that have experienced recent convective influence.
Additional Information
© 2022 American Geophysical Union. Issue Online: 18 March 2022; Version of Record online: 18 March 2022; Accepted manuscript online: 01 March 2022; Manuscript accepted: 27 February 2022; Manuscript revised: 11 February 2022; Manuscript received: 13 August 2021. Funding for this work was provided by NASA Grant No. NNX15AG61A. Additional support for H. M. Allen was provided by the National Science Foundation Graduate Research Fellowship under Grant No. DGE-1144469 and additional support for M. J. Kim was provided by the National Science Foundation Grant No. 1524860. The authors would like to thank the organizers of the ATom Mission, particularly S. C. Wofsy and T. B. Ryerson, for providing the opportunity to gather these data. We would also like to thank E. Czech, D. Jordan, and the people at ESPO, as well as the pilots and crew of the DC-8 for the infrastructural support that made these measurements possible. Data Availability Statement: The field data collected during the ATom deployments and used in this paper are available at https://doi.org/10.3334/ORNLDAAC/1581.Attached Files
Published - 2021JD035702.pdf
Accepted Version - 2021JD035702-acc.pdf
Supplemental Material - 2021jd035702-sup-0001-supporting_information_si-s01.pdf
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Additional details
- Alternative title
- H2O2 and CH3OOH (MHP) in the Remote Atmosphere: 2. Physical and Chemical Controls
- Alternative title
- Physical and Chemical Controls
- Eprint ID
- 113914
- Resolver ID
- CaltechAUTHORS:20220315-625973000
- NASA
- NNX15AG61A
- NSF Graduate Research Fellowship
- DGE-1144469
- NSF
- 1524860
- Created
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2022-03-16Created from EPrint's datestamp field
- Updated
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2023-10-06Created from EPrint's last_modified field
- Caltech groups
- Division of Geological and Planetary Sciences