Influence of the Background Nitrogen Oxides on the Tropospheric Ozone Depletion Events in the Arctic during Springtime

• Published in: Atmosphere
• Main Authors: Jiashu Zhou, Le Cao, Simeng Li
• Format: Article in Journal/Newspaper
• Language: English
• Published: MDPI AG 2020
• Subjects: concentration sensitivity analysis; ozone depletion events; nitrogen oxides; Meteorology. Climatology; QC851-999; Arctic
• Online Access: https://doi.org/10.3390/atmos11040344; https://doaj.org/article/7856a82c9c634228a0ca2104b8065128

Ozone depletion events (ODEs) in the springtime of the Arctic have been frequently observed since the early 1980s, and the correlation between the ozone mixing ratio during the ODEs and the nitrogen oxides (NO x ) concentration is still unclear. In the present study, the role of the background level of NO x in ODEs was investigated by using a box model implementing a chemical reaction mechanism containing 49 chemical species and 141 related reactions. A concentration sensitivity analysis was also applied to discover the dependence of the ozone mixing ratio during the ODEs on each constituent of the initial air composition. The simulation results showed that a critical value of the NO x background level exists, with which the ozone depletion rate is independent of the initial concentration of NO x , and the critical value was found to be approximately 55 ppt (ppt = part per trillion, 10 −12 mol/mol) in the present study. The concentration sensitivity analysis also showed that the existence of NO x has a two-sided impact on the depletion of ozone, depending on the initial amount of NO x . With a low background level of NO x (less than 55 ppt), the increase of the initial NO x can advance the ozone depletion. On the contrary, with a high initial NO x level (more than 55 ppt), NO x would delay the consumption of ozone during the ODEs.