Journal cover Journal topic
Atmospheric Chemistry and Physics An interactive open-access journal of the European Geosciences Union
Atmos. Chem. Phys., 17, 10565-10582, 2017
https://doi.org/10.5194/acp-17-10565-2017
© Author(s) 2017. This work is distributed under
the Creative Commons Attribution 3.0 License.
Research article
08 Sep 2017
Chemical processes related to net ozone tendencies in the free troposphere
Heiko Bozem1,a, Tim M. Butler2, Mark G. Lawrence2, Hartwig Harder1, Monica Martinez1, Dagmar Kubistin1,b, Jos Lelieveld1, and Horst Fischer1 1Atmospheric Chemistry Department, Max Planck Institute for Chemistry, P.O. Box 3060, 55020 Mainz, Germany
2Institute for Advanced Sustainability Studies e.V. Potsdam, Berliner Strasse 30, 14467 Potsdam, Germany
anow at: Institute for Atmospheric Physics, Johannes Gutenberg University, Mainz, Germany
bnow at: DWD, Hohenpeißenberg, Germany
Abstract. Ozone (O3) is an important atmospheric oxidant, a greenhouse gas, and a hazard to human health and agriculture. Here we describe airborne in situ measurements and model simulations of O3 and its precursors during tropical and extratropical field campaigns over South America and Europe, respectively. Using the measurements, net ozone formation/destruction tendencies are calculated and compared to 3-D chemistry–transport model simulations. In general, observation-based net ozone tendencies are positive in the continental boundary layer and the upper troposphere at altitudes above  ∼  6 km in both environments. On the other hand, in the marine boundary layer and the middle troposphere, from the top of the boundary layer to about 6–8 km altitude, net O3 destruction prevails. The ozone tendencies are controlled by ambient concentrations of nitrogen oxides (NOx). In regions with net ozone destruction the available NOx is below the threshold value at which production and destruction of O3 balance. While threshold NO values increase with altitude, in the upper troposphere NOx concentrations are generally higher due to the integral effect of convective precursor transport from the boundary layer, downward transport from the stratosphere and NOx produced by lightning. Two case studies indicate that in fresh convective outflow of electrified thunderstorms net ozone production is enhanced by a factor 5–6 compared to the undisturbed upper tropospheric background. The chemistry–transport model MATCH-MPIC generally reproduces the pattern of observation-based net ozone tendencies but mostly underestimates the magnitude of the net tendency (for both net ozone production and destruction).

Citation: Bozem, H., Butler, T. M., Lawrence, M. G., Harder, H., Martinez, M., Kubistin, D., Lelieveld, J., and Fischer, H.: Chemical processes related to net ozone tendencies in the free troposphere, Atmos. Chem. Phys., 17, 10565-10582, https://doi.org/10.5194/acp-17-10565-2017, 2017.
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Short summary
We present airborne measurements and model simulations in the tropics and mid-latitudes during GABRIEL and HOOVER, respectively. Based only on in situ data net ozone formation/destruction tendencies (NOPR) are calculated and compared to a 3-D chemistry transport model. The NOPR is positive in the continental boundary layer and the upper troposphere above 6 km. In the marine boundary layer and the middle troposphere ozone destruction prevails. Fresh convection shows strong net ozone formation.
We present airborne measurements and model simulations in the tropics and mid-latitudes during...
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