Impacts of chemical and meteorological data assimilation on air-quality and meteorological predictions in the Korean Peninsula

In the Korean Peninsula, intricate meteorological conditions influence fine particulate matter (PM) concentrations, making the improvement of both air-quality and meteorological forecasts crucial for better PM predictions. Data assimilation (DA) can help enhancing air-quality forecasts by reducing initial condition uncertainties of air-quality and meteorology. This study investigates the impacts of chemical and meteorological DA on air-quality and meteorological forecasts during a high PM event in the Korean Peninsula. Observational verification showed that the combined application of chemical and meteorological DA yielded the greatest improvements in air-quality and meteorological forecasts. While chemical DA primarily enhanced air-quality predictions, meteorological DA was essential for improving meteorological forecasts. 

The study also assessed the effects of chemical and meteorological DA on air-quality and meteorological forecasts in both DA cycling and non-cycling processes, with respect to the forecasts without DA. Based on the root-mean-square differences between forecasts with and without DA, the impacts of chemical and meteorological DA on air-quality forecasts were found to be similar in cycling and non-cycling processes. In the simultaneous chemical–meteorological DA experiment, the effects of the chemical DA and meteorological DA complemented each other. In the cycling DA process, chemical DA influenced meteorological forecasts, and meteorological DA affected air-quality forecasts due to cumulative DA effects. Chemical DA improved the absolute levels of PM in forecasts, while meteorological DA enhanced the spatiotemporal accuracy of PM distribution by refining transport processes. 

Consequently, simultaneous chemical–meteorological DA proved to be the most effective approach for changing air-quality and meteorological forecasts, and could offer substantial improvements in air-quality and meteorological forecasts in the Korean Peninsula. 

 

Acknowledgements

This study was supported by the National Research Foundation of Korea (2021R1A2C1012572) funded by the South Korean government (Ministry of Science and ICT) and the Yonsei Signature Research Cluster Program of 2024 (2024-22-0162).