Department of Atmospheric, Oceanic and Space Sciences, University of Michigan, Ann Arbor, MI 48109, USA.
Proc Natl Acad Sci U S A. 2010 Nov 16;107(46):19685-90. doi: 10.1073/pnas.1008336107. Epub 2010 Nov 1.
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.
地面臭氧浓度([O(3)])通常与地面空气温度呈直接线性关系。加利福尼亚州三十年来的测量结果提供了证据，表明在极高温度（>312 K）下，臭氧-温度斜率（Δm(O3-T)）发生了具有统计学意义的变化。这种 Δm(O3-T)导致 [O(3)]的平台或减少，反映了过氧乙酰硝酸盐对氮氧化物的固定作用减弱，以及高温下生物异戊二烯排放减少。尽管这些过程已被纳入全球和区域化学-气候模型中，但在之前的研究中并未注意到 Δm(O3-T)发生具有统计学意义的变化。未来的气候预测表明，这种 Δm(O3-T)响应的发生频率更高，空间分布更广，这使得基于历史观测到的线性关系来预测极端臭氧事件变得更加复杂。
