Spatiotemporal pattern analyses of AOD and NO2 VCD in Southeast Asian countries using low-Earth and geostationary orbit satellite data

Based on a number of low-Earth orbit (LEO) and geostationary (GEO) satellite data, the spatiotemporal pattern of aerosol optical depth (AOD) and the vertical column density of nitrogen dioxide (NO₂ VCD) was examined in Southeast Asian countries. Especially, we looked into the spatial distribution of AOD and NO₂ VCD in each administrative district, which is helpful for the inter-discipline studies about health risk or environmental policy impact in a local scale. For this study, we used the AOD obtained from the Moderate Resolution Imaging Spectroradiometer (MODIS) and Geostationary Environment Monitoring Spectrometer (GEMS) measurements, and NO₂ VCD from the Ozone Monitoring Instrument (OMI) measurements. First, climatological mean and diurnal variation of AOD and NO₂ VCD were examined in both national and city scale. We found that there is large difference of AOD and NO₂ VCD between national and city scale mean pattern in Thailand, Malaysia, and Indonesia, showing the higher developing region in Southeast Asia. Second, we found that contrast of monthly variation between mainland (e.g., Thailand, Lao PDR, etc.) and maritime (e.g., Malaysia, Indonesia, etc.) regions because the seasonal pattern and environmental properties used to be different according to the latitude. We will extend this analysis to other chemical species (SO₂ and HCHO) to prepare the typical air quality information in Southeast Asian countries, where the air quality issue is getting more important as the economic development is being accelerated. We will also investigate the effect of the biomass burning to the quantity variation of AOD and columnar density of gaseous pollutants more in detail.