NHM-Chem, the Japan Meteorological Agency’s Regional Meteorology – Chemistry Model: Model Evaluations toward the Consistent Predictions of the Chemical, Physical, and Optical Properties of Aerosols

Abstract

 Model performance of a regional-scale meteorology – chemistry model (NHM-Chem) has been evaluated for the consistent predictions of the chemical, physical, and optical properties of aerosols. These properties are essentially important for the accurate assessment of air quality and health hazards, contamination of land and ocean ecosystems, and regional climate changes due to aerosol-cloud-radiation interaction processes. Currently, three optional methods are available: the 5-category non-equilibrium, 3-category non-equilibrium, and bulk equilibrium methods. These three methods are suitable for the predictions of regional climate, air quality, and operational forecasts, respectively. In this paper, the simulated aerosol chemical, physical, and optical properties and their consistency were evaluated by using various observation data in East Asia. The simulated mass, size, and deposition of SO₄^2- and NH₄⁺ agreed well with the observations, whereas those of NO₃^-, sea-salt, and dust needed improvement. The simulated surface mass concentration (PM₁₀ and PM_2.5) and spherical extinction coefficient agreed well with the observations. The simulated aerosol optical thickness and dust extinction coefficient were significantly underestimated.