Simulation of ozone-vegetation coupling and feedback in China using multiple ozone damage schemes

Abstract. As a phytotoxic pollutant, surface ozone (O₃) not only affects plant physiology but also influences meteorological fields and air quality by altering leaf stomatal functions. Previous studies revealed strong feedbacks of O₃-vegetation coupling in China but with large uncertainties due to the applications of varied O₃ damage schemes and chemistry-vegetation models. In this study, we quantify the O₃ vegetation damage and the consequent feedbacks to surface meteorology and air quality in China by coupling two O₃ damage schemes (S2007 vs. L2013) into a fully coupled regional meteorology-chemistry model. With different schemes and damaging sensitivities, surface O₃ is predicted to decrease summertime gross primary productivity by 5.5 %–21.4 % and transpiration by 5.4 %–23.2 % in China, in which the L2013 scheme yields 2.5–4 times of losses relative to the S2007 scheme. The damages to photosynthesis of sunlit leaves are ~2.6 times that of shaded leaves in the S2007 scheme but show limited differences in the L2013 scheme. Though with large discrepancies in offline responses, the two schemes yield similar magnitude of feedback to surface meteorology and O₃ air quality. The O₃-induced damage to transpiration increases national sensible heat by 3.2–6.0 W m^-2 (8.9 % to 16.2 %) while reduces latent heat by 3.3–6.4 W m^-2 (-5.6 % to -17.4 %), leading to a 0.2–0.51 °C increase in surface air temperature and a 2.2–3.9 % reduction in relative humidity. Meanwhile, surface O₃ concentrations on average increase by 1.3–3.3 μg m^-3 due to the inhibitions of stomatal uptake and the anomalous enhancement in isoprene emissions, the latter of which is attributed to the surface warming by O₃-vegetaion coupling. Our results highlight the importance of O₃ control in China due to its adverse effects on ecosystem functions, deterioration of global warming, and exacerbation of O₃ pollution through the O₃-vegetation coupling.