Multi-model downscaling simulations of regional climate and air quality in China

In this study, a multi-model ensemble of regional climate and air quality coupling model system was established to evaluate current climate and air pollution in China during 2010-2014. Meteorological initial and boundary conditions were obtained from the multi earth system models used in the Coupled Model Intercomparison Project Phase 6 (CMIP6) with a dynamical downscaling method and the National Centers for Environmental Prediction Final Analysis (NCEP-FNL) reanalysis data. These downscaling data under the historical scenario and FNL data were applied to driven the Weather Research and Forecasting model coupled to Chemistry (WRF-Chem) to simulate current climate and air quality. A comprehensive evaluation of the current five years was conducted against the ground-level meteorological and chemical observations. The performances for the 2 m temperature were very well and consistently overestimated the wind speed at 10 m by 0.8~1.2 m/s. PM_2.5 and ozone concentrations were underestimated by the downscaling data driven simulations compared with the FNL data. The model performance was relatively well and can be used to study the impacts of climate change on China's future air quality and pollution events in the context of carbon neutrality and clean air, which may shed light on policy formulation for medium and long-term air quality management and climate change alleviation.