Observed suppression of ozone formation at extremely high temperatures due to chemical and biophysical feedbacks.
Ground level ozone concentrations ([O(3)]) 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 (Δm(O3-T)) under extremely high temperatures (> 312 K). This Δm(O3-T) leads to a plateau or decrease in [O(3)], 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 Δm(O3-T) has not been noted in prior studies. Future climate projections suggest a more frequent and spatially widespread occurrence of this Δm(O3-T) response, confounding predictions of extreme ozone events based on the historically observed linear relationship.
Department of Atmospheric, Oceanic and Space Sciences, University of Michigan, Ann Arbor, MI 48109, USA. alsteiner@umich.edu
Allison L
AL
Steiner
Adam J
AJ
Davis
Sanford
S
Sillman
Robert C
RC
Owen
Anna M
AM
Michalak
Arlene M
AM
Fiore
D055592:Biophysical Phenomena; D002070:Butadienes / Q000032:analysis; D002140:California; D055598:Chemical Phenomena; D003198:Computer Simulation; D005246:Feedback; D005843:Geography; D045782:Hemiterpenes / Q000032:analysis; D006358:Hot Temperature; D015233:Models, Statistical; D010126:Ozone / Q000032:analysis*; D010420:Pentanes / Q000032:analysis
D002070:Butadienes; D045782:Hemiterpenes; D010420:Pentanes; C005059:isoprene; D010126:Ozone