Articles | Volume 22, issue 23
Research article
30 Nov 2022
Research article |  | 30 Nov 2022

The unexpected high frequency of nocturnal surface ozone enhancement events over China: characteristics and mechanisms

Cheng He, Xiao Lu, Haolin Wang, Haichao Wang, Yan Li, Guowen He, Yuanping He, Yurun Wang, Youlang Zhang, Yiming Liu, Qi Fan, and Shaojia Fan

Data sets

Historical air quality data in China X. L. Wang

AQS observation data US EPA

E2a observation data EU EEA

ERA5 global reanalysis (!/search?text=ERA5) H. Hersbach, B. Bell, P. Berrisford, S. Hirahara, A. Horányi, J. Muñoz-Sabater, J. Nicolas, C. Peubey, R. Radu, D. Schepers, A. Simmons, C. Soci, S. Abdalla, X. Abellan, G. Balsamo, P. Bechtold, G. Biavati, J. Bidlot, M. Bonavita, G. De Chiara, P. Dahlgren, D. Dee, M. Diamantakis, R. Dragani, J. Flemming, R. Forbes, M. Fuentes, A. Geer, L. Haimberger, S. Healy, R. J. Hogan, E. Hólm, M. Janisková, S. Keeley, P. Laloyaux, P. Lopez, C. Lupu, G. Radnoti, P. de Rosnay, I. Rozum, F. Vamborg, S. Villaume, and J.-N. Thépaut

Short summary
We report that nocturnal ozone enhancement (NOE) events are observed at a high annual frequency of 41 % over 800 sites in China in 2014–2019 (about 50 % higher than that over Europe or the US). High daytime ozone provides a rich ozone source in the nighttime residual layer, determining the overall high frequency of NOE events in China, and enhanced atmospheric mixing then triggers NOE events by allowing the ozone-rich air in the residual layer to be mixed into the nighttime boundary layer.
Final-revised paper