Correlation between Black Carbon and CO on Urban and Wildfire Area in East Asia From Satellite Remote Sensing

Recent development in satellite remote sensing, with its global coverage now enables us to investigate correlation between aerosols and pollutant gases. MOPITT (Measurement of Pollution in the Troposphere) onboard the Terra satellite launched in 1999 has observed CO(carbon monoxide) density, and MODIS(Moderate Resolution Imaging Spectroradiometer) has observed AOD(Aerosol Optical Depth). Increases of CO, a very important gas in tropospheric chemistry, in atmosphere can reduce the self- purification ability of atmosphere, thus modifies atmospheric chemical, physical, and climatological properties. Direct radiative forcing of black carbon aerosol has been regarded as a potential factor causing global warming(IPCC, 2007). MODIS-OMI algorithm is used to investigate correlation between CO and black carbon AOD. This algorithm uses OMI's AI(Aerosol Index) to determine radiative absorption of aerosol and MODIS's AE(Angstrom Exponent) to determine size of aerosol (Kim et al., 2007). Using this algorithm, we can classify the aerosol into 4 types - black carbon, soil dust, sulfate, and seasalt(Higurashi and Nakajima, 2002; Kim et al., 2007). Main sources of both CO and black carbon are related to incomplete combustion which results from wildfires and urban industrial emissions, but sinks are different. This research investigates how the correlation between CO and black carbon varies according to these two sources in East Asia. We use the MODIS Land cover, MODIS fire counts, sulfate by MODIS-OMI algorithm, and OMI's nitrogen dioxide data to distinguish urban and wildfires region. To scrutinize how the correlation between CO and black carbon varies in relation to urban and wildfires, East Asia is divided into 2 areas - A (urban industrial emissions are dominant) and B (wildfires are dominant). The density of black carbon and CO in both A and B region is high, but that in A region is higher than that in B region.