Spatial distribution of the source-receptor relationship of sulfur in Northeast Asia

Abstract. The spatial distribution of the source-receptor relationship (SRR) of sulfur over Northeast Asia was examined using a chemical transport model (RAQM) off-line coupled with a meteorological model (MM5). The simulation was conducted for the entire year of 2002. The results were evaluated using monitoring data for six remote stations of the Acid Deposition Monitoring Network in East Asia (EANET). The modeled SO 2 and O 3 concentrations agreed well with the observations quantitatively. The modeled aerosol and wet deposition fluxes of SO 4 2− were underestimated by 30 % and 50 %, respectively. The domain was divided into 5 source-receptor regions: (I) North China; (II) Central China; (III) South China; (IV) South Korea; and (V) Japan. The sulfur deposition in each receptor region amounted to about 50–75 % of the emissions from the same region. The largest contribution to the deposition in each region was originated from the same region, accounting for 53–84 %. The second largest contribution was due to Region II, supplying 14–43 %. The spatial distributions of the SRRs revealed that subregional values varied by about two times more than regional averages due to nonuniformity across the deposition fields. Examining the spatial distributions of the deposition fields was important for identifying subregional areas where the deposition was highest within a receptor region. The horizontal distribution changed substantially according to season.