Observed suppression of ozone formation at extremely high temperatures due to chemical and biophysical feedbacks
Ground level ozone concentrations ([O3]) typically show a direct linear relationship with surface air temperature. Three decades of California measurements provide evidence of a statistically significant change in the ozone-temperature slope (ΔmO3-T) under extremely high temperatures (> 312 K). This ΔmO3-T leads to a plateau or decrease in [O3], reflecting the diminished role of nitrogen oxide sequestration by peroxyacetyl nitrates and reduced biogenic isoprene emissions at high temperatures. Despite inclusion of these processes in global and regional chemistry-climate models, a statistically significant change in ΔmO3-T has not been noted in prior studies. Future climate projections suggest a more frequent and spatially widespread occurrence of this ΔmO3-T response, confounding predictions of extreme ozone events based on the historically observed linear relationship.
- PNAS-2010-Steiner-19685-90.pdf application/pdf 2.19 MB Download File
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- PNAS : Proceedings of the National Academy of Sciences