Annual sulfur deposition through fog, wet and dry deposition in the Kinki Region of Japan

This study estimated annual sulfur (SO 2 + SO 4 2−) deposition through fog, wet and dry deposition in the Kinki Region of Japan from April 2004 to March 2005. The numerical models used in this study include the Weather Research and Forecasting model (WRF), the Community Multiscale Air Quality model (CMAQ), and a fog deposition model. WRF well predicted mountain fog at Mt. Rokko, the meteorology near the ground surface in the Kinki Region and the upper air meteorology in Japan during the simulation period. CMAQ well predicted the long-range atmospheric transport of aerosol SO 4 2− from the Asian Continent to Japan. The mean SO 4 2− concentration in fog water was approximately 6 times higher than that in precipitation in the Kinki Region. Ratios of fog water deposition to precipitation reached up to more than 10% in some mountainous areas in the Kinki Region. Consequently, the amount of sulfur deposition through fog water deposition was larger than that through dry deposition and comparable to that through wet deposition in some mountainous areas in the Kinki Region. ► We estimated sulfur deposition through fog, wet and dry deposition in Kinki Region. ► WRF/CMAQ well simulated the meteorology and air quality. ► SO 4 2− concentration in fog water was 6 times higher than that in precipitation. ► Fog water deposition was large in the mountainous areas with high fog frequency. ► Fog water deposition is important in some mountains in Kinki Region of Japan.