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 gridd..., Inverse Distance Weighting (IDW) to interpolate (NIER) ground station chemical abundances to a fine grid (1/20th degree), followed by spatial averaging to 10th degree resolution., , # KORUS-AQ gridded O3, NOx, and CO observations created using ground station

[https://doi.org/10.5061/dryad.sf7m0cgf5](https://doi.org/10.5061/dryad.sf7m0cgf5)

A gridded observational dataset of surface level ozone (O3), carbon monoxide (CO), and nitrogen oxides (NOx) in South Korea during KORUS-AQ time period created using an inverse distance weighting interpolation procedure.

## Description of the data and file structure

### Gridded data products:

#### KORUS-AQ\_gridded\_O3\_CO\_NOx\_Q.nc

0.1x0.1 degree gridded hourly O3, CO, and NOx obervations from NIER stations across South Korea during the KORUS. Also includes the effective density of observations for each grid cell (number of stations within 10 km).

### Analysis data:

Datasets used to generate results and figures in the associated manuscript.

#### Ground\_Station\_Hourly\_O3\_CO\_NOx.nc

Hourly averages of the 5 minute individual NIER site O3, CO, and NOx data used to produce the gridded product. Also contains prediction...