Development of the Korean Air Chemistry Modeling System version 2.0 (K_ACheMS v2.0) and its performance of operational mode

The Korean Air Chemistry Modeling System (K_ACheMS) has been developed to enhance the predictability of PM_2.5 in South Korea. In the current version (v2.0) of K_ACheMS, two meteorological models are used to produce meteorological fields. The first model is version 4.1.5 of the Weather Research and Forecasting (WRF) model. The WRF v4.1.5 model is initialized using four cycles (00Z, 06Z, 12Z, and 18Z) of real-time Global Forecasting System (GFS) data from the National Oceanic and Atmospheric Administration (NOAA). The other model is the Regional Data Assimilation and Prediction System (RDAPS), which is the regional operational model of the Korean Meteorological Administration (KMA) based on the Unified Model (UM) developed by the Met Office of the United Kingdom.

For air quality model simulations, the Community Multi-scale Air Quality version GIST (CMAQ-GIST) model has been developed based on the CMAQ v5.2.1 model. The CMAQ-GIST model mainly uses a modified version of the Statewide Air Pollution Research Center 07 (SAPRC07TC) chemical mechanism with several important updates, including the following: (i) daytime HONO photo-chemistries; (ii) heterogeneous HO₂ reactions; (iii) gas- and aqueous-phase halogen chemistries; and (iv) new yield data for SOA formation acquired from multiple smog chamber experiments conducted under typical conditions of northeast Asia. In order to update chemical initial conditions for the CMAQ-GIST model simulations, a three-dimensional variational (3D-VAR) method is applied to the operational mode of K_ACheMS.

Here, we introduce the development of the K_ACheMS v2.0 and present the current performances of the operational mode of K_ACheMS v2.0 by comparing the ground-based observations in South Korea.