Gridded surface O₃, NO_x, 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).