Impacts of ozone-vegetation feedbacks on surface ozone in a coupled climate-chemistry-ecosystem model

<jats:p>Abstract. Surface ozone (O3) is strongly influenced by interactions between atmospheric chemistry and terrestrial ecosystems, yet these feedbacks remain insufficiently represented in Earth system models. Here, we develop a fully coupled O3-vegetation interaction framework by integrating the terrestrial ecosystem model iMAPLE into the ECHAM-HAMMOZ Earth system model. The coupled model explicitly represents three major land-atmosphere interaction pathways, including dynamic biogenic volatile organic compound (BVOC) emissions, vegetation-mediated O3 dry deposition, and O3-induced vegetation damage. These feedback pathways exert heterogeneous impacts on surface O3 concentrations due to spatial variations in vegetation characteristics and nonlinear chemical sensitivities. Changes in monoterpene emissions cause the largest global effect with widespread reductions in surface O3, whereas isoprene-driven responses vary among regions with different chemical sensitivities. In regions with high anthropogenic emissions, such as East Asia, vegetation-mediated changes in BVOCs and dry deposition substantially amplify O3 responses. The O3-induced vegetation damage further modifies atmospheric chemistry by reducing BVOC emissions through leaf area loss while increasing surface O3 by inhibiting stomatal conductance. Incorporating these processes decreases simulated global surface O3 concentrations and alleviates the positive bias in the original model, particularly over China (relative mean bias decreases from 31.5 % to 29.7 %) and the U.S. (from 19.0 % to 7.8 %). These results demonstrate that interactive O3-vegetation feedbacks are essential for improving the representation of atmospheric composition and ecosystem–atmosphere interactions in Earth system models.</jats:p>