Surface erythemal UV radiation is mainly affected by total column ozone, aerosols, clouds, and solar zenith angle. The effect of ozone on the surface UV radiation has been explored many times in the previous studies due to the decrease of ozone layer. In this study, we calculated the effect of aerosols on the surface UV radiation as well as that of ozone using data acquired from Ozone Monitoring Instrument (OMI). First, ozone, aerosol optical depth (AOD), and surface erythemal UVB radiation measured from satellite are compared with those from ground measurements. The results showed that the comparison for ozone was good with r 2 of 0.92. For aerosol, there was difference between satellite measurements and surface measurements due to the insufficient information on aerosol in the retrieval algorithm. The r 2 for surface erythemal UV radiation was high (∼0.94) but satellite measurements showed about 30% larger values than surface measurements on average by not considering the effect of absorbing aerosols in the retrieval process from satellite measurements. Radiative amplification factor (RAF) is used to access the effect of ozone and aerosol quantitatively. RAF for ozone was 0.97∼1.49 with solar zenith angle. To evaluate the effect of aerosol on the surface UV radiation, only clear-sky pixel data were used and solar zenith angle and total column amount of ozone were fixed. Also, RAF for aerosol was assessed according to the single scattering albedo (SSA) of aerosols. The results showed that RAF for aerosol with smaller SSA (< 0.90) was larger than that for with larger SSA (> 0.90). The RAF for aerosol was 0.09∼0.22 for the given conditions which was relatively small compared to that for ozone. However, considering the fact that aerosol optical depth can change largely in time and space while the total column amount of ozone does not change very much, it needs to include the effect of aerosol to predict the variations of surface UV radiation more correctly.

Monitoring of climate change and atmospheric environment by satellite measurements has been increased in recent years. In this study, nitrogen dioxide (NO2) measurements from Ozone Monitoring Instrument (OMI) were compared with surface measurements over the Korean peninsula. NO2 from OMI measurements showed high values and also showed seasonal variations such as high concentration in winter and low in summer over metropolitan areas while NO2 concentration at national background station was low and did not clearly show seasonal variations. Surface measurements showed similar temporal and spatial variations to those of satellite measurement. The comparison between satellite measurements and surface measurements showed that the correlation between them was higher in urban area (r=0.64 at Seoul and r=0.63 at Daegu) than in national background stations (r=0.37 at Jeju) because the concentration in urban area was relatively high so that the variation of NO2 concentration could be detected better than at national background stations by satellite. Satellite can effectively measure the emission and transport of pollutants with no limitations in spatial coverage.

The evaluation of regional air quality model is needed to assess model’s ability to simulate concentrations and longterm variability of atmospheric constituents. The use of satellite data in air quality application has been increasing and has contributed in improving air quality model. In this study, satellite data obtained from Ozone Monitoring Instrument (OMI) are compared with ground-based measurements and simulation results from Community Multiscale Air Quality (CMAQ) modeling system for nitrogen oxides (NO2) and sulfur dioxides (SO2) over the East Asia and Korean peninsula. Monthly and seasonal variations of column amounts from surface measurements and CMAQ simulation are compared with those from OMI measurements. Also, long range transboundary air pollution over the East Asia was analyzed both from model and satellite measurements. Air quality model results showed similar temporal and seasonal variations with satellite data. Both model result and satellite measurement for NO2 and SO2 showed higher concentration in winter than in summer and NO2 had higher correlation between model results and satellite data than SO2. Also, the results showed that satellite measurements of SO2 was higher than modeling results in both urban (Seoul) and background (Taean) region. Concentration from model was very low in summer compared to that from satellite due to the excessive washout by rain in the model. However, it needs more analysis to better understand model processes and the effectiveness of satellite measurement. The temporal and spatial analysis for O3, NO2, and SO2 using satellite data made it possible to monitor distribution, emission source, and long-range transport of pollutants over wide area.