东亚地区春季硫氧化物浓度分布及其收支研究

Numerical Study on Concentration Distributions of Sulfur Compounds and Their Budgets over East Asia in the Springtime

利用一个耦合的区域化学输送模式系统，模拟了2001年3～4月间东亚区域二氧化硫（SO2）和硫酸盐（SO4^2-）气溶胶浓度的时空分布，并分析了它们的来源、输送、转化和沉降过程在浓度形成中的作用。为了检验模拟结果的合理性，侧重分析了4月9～12日SO2的输送和转化过程。在这一期间，SO2浓度观测资料显示，日本的观测站Happo、Oki和Hedo周围及日本海部分海域先后经历了一次SO2浓度高值。模拟结果表明，日本东京附近的三宅岛火山喷发严重影响了日本列岛和周边海域SO2和SO4^2-气溶胶的分布，是引起观测站周围及日本海部分海域SO2浓度高值的主要原因。3月1日至4月31日间的硫收支分析显示，气相与液相化学过程在SO2的氧化过程中具有同等的重要性，模拟区域排放的硫氧化物中有约42％（其中约25％为SO2）被输送到模拟区域以外，约57％（约35％为湿沉降）沉积在模拟区域内。

A coupled regional chemical transport modeling system is applied to investigate the time spatial variations in sulfur dioxide and sulfate aerosol concentration over East Asia, especially to illustrate transport and chemical conversion of sulfur dioxide on 9-12 April, when the Happo, Oki and Hedo sites in Japan and part of the Japan Sea experienced a high sulfur dioxide episode revealed in the observations. Analysis of model results shows that the emissions from the Miyakejima volcano located to the south of Tokyo, Japan, had a strong impact on sulfur dioxide and sulfate aerosol concentration distributions over Japan islands and the surrounding areas, and were the dominant contributor to the high sulfur dioxide episode over the observation sites and the Japan Sea. Sulfur budgets for March 1 to April 30 indicate that the gas-phase and the aqueous phase had the same importance in oxidizing sulfur oxide, and about 42% sulfur compounds ≈25% in sulfur dioxide） emitted in the model domain was transported out, while about 57% ≈35% by wet removal processes） deposited in the domain.