Steady state free radical budgets and ozone photochemistry during TOPSE

Christopher A. Cantrell, L. Mauldin, M. Zondlo, F. Eisele, E. Kosciuch, R. Shetter, B. Lefer, S. Hall, T. Campos, B. Ridley, J. Walega, A. Fried, B. Wert, F. Flocke, A. Weinheimer, J. Hannigan, M. Coffey, E. Atlas, S. Stephens, B. HeikesJ. Snow, D. Blake, N. Blake, A. Katzenstein, J. Lopez, E. V. Browell, J. Dibb, E. Scheuer, G. Seid, R. Talbot

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Abstract

A steady state model, constrained by a number of measured quantities, was used to derive peroxy radical levels for the conditions of the Tropospheric Ozone Production about the Spring Equinox (TOPSE) campaign. The analysis is made using data collected aboard the NCAR/NSF C-130 aircraft from February through May 2000 at latitudes from 40° to 85°N, and at altitudes from the surface to 7.6 km. HO2 + RO2 radical concentrations were measured during the experiment, which are compared with model results over the domain of the study showing good agreement on the average. Average measurement/model ratios are 1.04 (σ = 0.73) and 0.96 (σ = 0.52) for the MLB and HLB, respectively. Budgets of total peroxy radical levels as well as of individual free radical members were constructed, which reveal interesting differences compared to studies at lower latitudes. The midlatitude part of the study region is a significant net source of ozone, while the high latitudes constitute a small net sink leading to the hypothesis that transport from the middle latitudes can explain the observed increase in ozone in the high latitudes. Radical reservoir species concentrations are modeled and compared with the observations. For most conditions, the model does a good job of reproducing the formaldehyde observations, but the peroxide observations are significantly less than steady state for this study. Photostationary state (PSS) derived total peroxy radical levels and NO/NO2 ratios are compared with the measurements and the model; PSS-derived results are higher than observations or the steady state model at low NO concentrations.

Original languageEnglish (US)
Pages (from-to)9-1
Number of pages9
JournalJournal of Geophysical Research D: Atmospheres
Volume108
Issue number4
StatePublished - Feb 27 2003
Externally publishedYes

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ASJC Scopus subject areas

  • Geophysics
  • Forestry
  • Oceanography
  • Aquatic Science
  • Ecology
  • Water Science and Technology
  • Soil Science
  • Geochemistry and Petrology
  • Earth-Surface Processes
  • Atmospheric Science
  • Earth and Planetary Sciences (miscellaneous)
  • Space and Planetary Science
  • Palaeontology

Cite this

Cantrell, C. A., Mauldin, L., Zondlo, M., Eisele, F., Kosciuch, E., Shetter, R., Lefer, B., Hall, S., Campos, T., Ridley, B., Walega, J., Fried, A., Wert, B., Flocke, F., Weinheimer, A., Hannigan, J., Coffey, M., Atlas, E., Stephens, S., ... Talbot, R. (2003). Steady state free radical budgets and ozone photochemistry during TOPSE. Journal of Geophysical Research D: Atmospheres, 108(4), 9-1.