KORUS-AQ gridded O3, NOx, and CO observations created using ground station data

We present gridded surface air quality datasets over South Korea for three
key species – ozone (O3), carbon monoxide (CO), and nitrogen oxides (NOx)
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 NOx 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 NOx 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 NOx in most site–dense urban
centres (SMA, Cheongju, Gwangju, Daegu, Changwon, and Busan).