Response of a coupled chemistry-climate model to changes in aerosol emissions: Global impact on the hydrological cycle and the tropospheric burdens of OH, ozone, and NO_x

In this study, we analyze the response of the coupled chemistry-climate system to changes in aerosol emissions in fully coupled atmospheric chemistry-climate-slab ocean model simulations; only the direct radiative effect of aerosols and their uptake of chemical species are considered in this study. We show that, at the global scale, a decrease in emissions of the considered aerosols (or their precursors) produces a warmer and moister climate. In addition, the tropospheric burdens of OH and ozone increase when aerosol emissions are decreased. The ozone response is a combination of the impact of reduced heterogeneous uptake of N₂O₅ and increased ozone loss in a moister atmosphere. Under reduced aerosol emissions, the tropospheric burden of NO_x (NO + NO₂) is strongly reduced by an increase in nitric acid formation but also increased by the reduced N₂O₅ uptake. Finally, we discuss the significant difference found between the combined impact of all aerosols emissions and the sum of their individual contributions.