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Published April 27, 2016 | Published
Journal Article Open

Convective transport and scavenging of peroxides by thunderstorms observed over the central U.S. during DC3

Abstract

One of the objectives of the Deep Convective Clouds and Chemistry (DC3) field experiment was to determine the scavenging of soluble trace gases by thunderstorms. We present an analysis of scavenging of hydrogen peroxide (H_2O_2) and methyl hydrogen peroxide (CH_3OOH) from six DC3 cases that occurred in Oklahoma and northeast Colorado. Estimates of H_2O_2 scavenging efficiencies are comparable to previous studies ranging from 79 to 97% with relative uncertainties of 5–25%. CH_3OOH scavenging efficiencies ranged from 12 to 84% with relative uncertainties of 18–558%. The wide range of CH_3OOH scavenging efficiencies is surprising, as previous studies suggested that CH_3OOH scavenging efficiencies would be <10%. Cloud chemistry model simulations of one DC3 storm produced CH_3OOH scavenging efficiencies of 26–61% depending on the ice retention factor of CH_3OOH during cloud drop freezing, suggesting ice physics impacts CH_3OOH scavenging. The highest CH_3OOH scavenging efficiencies occurred in two severe thunderstorms, but there is no obvious correlation between the CH_3OOH scavenging efficiency and the storm thermodynamic environment. We found a moderate correlation between the estimated entrainment rates and CH_3OOH scavenging efficiencies. Changes in gas-phase chemistry due to lightning production of nitric oxide and aqueous-phase chemistry have little effect on CH_3OOH scavenging efficiencies. To determine why CH_3OOH can be substantially removed from storms, future studies should examine effects of entrainment rate, retention of CH_3OOH in frozen cloud particles during drop freezing, and lightning-NO_x production.

Additional Information

© 2016 American Geophysical Union. Received 25 NOV 2015; Accepted 10 APR 2016; Accepted article online 13 APR 2016; Published online 29 APR 2016. The authors thank the DC3 Science and Logistics teams for the successful execution of the DC3 field campaign. Data from the DC3 field project can be found at http://data.eol.ucar.edu/master_list/?project=DC3. The aircraft data are also located at http://www-air.larc.nasa.gov/cgi-bin/ArcView/dc3-seac4rs. Output from the model simulations can be obtained upon request to M. Barth (barthm@ucar.edu). We appreciate Conrad Ziegler (NOAA/NSSL) and his team as well as the NCAR/EOL ISS team for the radiosonde data. G. Diskin and his team are acknowledged for their DC-8 water vapor and CO measurements. We are grateful for the informative weather summaries provided by Morris Weisman and Craig Schwartz during the DC3 field campaign. We value the contributions of John Orlando and the comments on the paper by Sasha Madronich, Rebecca Hornbrook and the three anonymous reviewers. The National Center for Atmospheric Research is sponsored by the National Science Foundation. The INSTAAR group acknowledges NSF and NASA under grant awards AGS-1261559 and NNX12AMO8G, respectively, for funding their participation in the measurements and analysis. The Caltech group thanks NASA for funding their participation in DC3 and contribution to this analysis via grants NNX12AC06G and NNX14AP46G-ACCDAM. N. Blake and D. Blake acknowledge support for DC3 measurements from NASA award NNX12AB76G. C. Homeyer was supported by NSF under grant AGS-1522910. W. H. Brune, L. Zhang, J. Mao, and X. Ren were supported by NASA grant NNX12AB84G. T. B. Ryerson, J. Peischl, and I. B. Pollack were supported under the NOAA Climate Change and NOAA Health of the Atmosphere programs, with participation in DC3 made possible by NASA grant NNH12AT30I. R. C. Cohen and B. A. Nault were supported by NASA grant NNX12AB79G. B. A. Nault was also supported by the NSF Graduate Research Fellowship under grant DGE 1106400. L. G. Huey and X. Liu were supported by NASA grant NNX12AB77G.

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August 22, 2023
Modified:
October 20, 2023