Gridded surface O3, NOx, and CO abundances for model metrics from the South Korean ground station network

Abstract. We present gridded surface air quality datasets over South Korea for three key species – ozone (O₃), carbon monoxide (CO), and nitrogen oxides (NO_x) during the timeframe of the Korea–US Air Quality (KORUS–AQ) mission (May–June 2016). The tenth degree hourly averaged abundances are constructed from the 300+ air quality network sites using inverse distance weighting with simple declustering. Cross–comparing the interpolated fields against the site data that was used to create them reveals high prediction skill for O₃ (80 %) throughout South Korea, and moderate skill (60 %) for CO and NO_x on average in densely observed regions after individual mean bias corrections. The gridded O₃ and CO interpolations predict the NASA DC–8 observations in the planetary boundary layer (PBL) with high skill (80 %) in the Seoul Metropolitan Area (SMA) after subtracting the mean bias. DC–8 NO_x observations were much less predictable on account of consistently negative vertical gradients within the PBL. Our gridded products capture the mean and variability of O₃ throughout South Korea, and of CO and surface NO_x in most site–dense urban centres (SMA, Cheongju, Gwangju, Daegu, Changwon, and Busan).