Modeling Studies for the Effects of Spring-Time Mineral Aerosols on the Transport and Deposition of Sulfur in East Asia Using the STEM-II Model

The impact of spring-time mineral aerosols on the transport and deposition of sulfur in East Asia during the period of March 1 through March 14, 1994 is studied using a three-dimensional regional-scale atmospheric chemistry model (STEM-II model) coupled with the mineral dust processes. The results indicate that the areas of the maximum amounts of sulfur dioxide and particulate sulfate are located in the eastern China. The sulfur emitted from the volcanoes in Japan is responsible for 10% to 30% of the atmospheric sulfur in the local region during this time period, which is comparable with the aircraft-based measurements. The sulfur transport is largely limited to the 2~6 km level of the atmosphere, with the maximum flux occurring in the 30oN to 40oN hand which is consistent with the region of maximum anthropogenic emissions. The distributions of the average column amounts of the particulate sulfate in this region are shown, and the directive radiative forcing of the particulate sulfate on the temperature variation of the earth-atmosphere system is also discussed.