The Impact of the Direct Effect of Aerosols on Meteorology and Air Quality Using Aerosol Optical Depth Assimilation During the KORUS‐AQ Campaign
Jung, J., A. Souri, Cheung Wong, S. Lee, AND J. Kim. The Impact of the Direct Effect of Aerosols on Meteorology and Air Quality Using Aerosol Optical Depth Assimilation During the KORUS‐AQ Campaign. JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES. American Geophysical Union, Washington, DC, 124(14):8303-8319, (2019).
This study found that aerosols in the atmosphere increase surface aerosol concentrations through changing the meteorology. It also showed that AOD assimilation using the GOCI AOD as geostationary data enhances the performance of the model and increases the reliability of the quantification of aerosol feedback. Thus, the approach used here would be useful in East Asia, with its consistently high levels of aerosols concentrations. Without a concerted effort to reduce aerosol concentrations (e.g., emission control), this situation, under a stable atmosphere, will persist with considerably enhanced feedback. Thus, a rigorous study that examines the effects of aerosol forcing on climate change would be a worthy direction of research.
To quantify the impact of the direct aerosol effect accurately, this study incorporated the Geostationary Ocean Color Imager (GOCI) aerosol optical depth (AOD) into a coupled meteorology‐chemistry model. We designed three model simulations to observe the impact of AOD assimilation and aerosol feedback during the KORUS‐AQ campaign (May–June 2016). By assimilating the GOCI AOD with high temporal and spatial resolutions, we improve the statistics from the comparison AOD and AERONET data (root‐mean‐square error: 0.12, R: 0.77, index of agreement: 0.69, mean‐absolute error: 0.08). The inclusion of the direct effect of aerosols produces the best model performance (root‐mean‐square error: 0.10, R: 0.86, index of agreement: 0.72, mean‐absolute error: 0.07). AOD values increased as much as 0.15, which is associated with an average reduction in solar radiation of ‐31.39 W/m2, a planetary boundary layer height (‐104.70 m), an air temperature (‐0.58 °C), and a surface wind speed (‐0.07 m/s) over land. In addition, concentrations of major gaseous and particulate pollutants at the surface (SO2, NO2, NH3, urn:x-wiley:2169897X:media:jgrd55644:jgrd55644-math-0001, urn:x-wiley:2169897X:media:jgrd55644:jgrd55644-math-0002, urn:x-wiley:2169897X:media:jgrd55644:jgrd55644-math-0003, and PM2.5) increase by 7.87–34%, while OH concentration decreases by ‐4.58%. Changes in meteorology and air quality appear to be more significant in high‐aerosol loading areas. The integrated process rate analysis shows decelerated vertical transport, resulting in an accumulation of air pollutants near the surface and the amount of nitrate, which is higher than that of sulfate because of its response to reduced temperature. We conclude that constraining aerosol concentrations using geostationary satellite data is a prerequisite for quantifying the impact of aerosols on meteorology and air quality.