Modeling studies on sulfur deposition and transport in East Asia

A three dimensional regional Eulerian model of sulfur deposition and tranport has been developed. It includes emission, transport, diffusion, gas-phase and aqeous-phase chemical process, dry depostion, rainout and washout process. A ''looking up table'' method is provided to deal with the gas-phase chemical process including sulfur transfer. Calculated values have reasonable agreement with observations. Distribution of sulfur deposition and transport in East Asia are also analyzed in the paper. Simulation shows that sulfate (SO42-) is the main substance to transport in long range transport. Some amount of sulfur emission of different countries transport across boundaries, but the main origin of sulfur deposition in each country in East Asia is from herself. Furthermore, some transport paths on different layers and outlet or inlet zones are found.