台风作为发生、发展于海洋的天气系统,其对沿海城市海盐气溶胶的影响究竟如何值得探究.利用2011年第17号强台风“纳沙”影响深圳期间的深圳气象局竹子林大气成分站的MARGA(Monitoring Instrument for Aerosols and Gases)数据,研究了期间台风对深圳PM_(2.5)中海盐气溶胶(以下简称海盐气溶胶)的影响.结果发现,受台风外围下沉气流的影响,各气溶胶成分的浓度均有明显的增加.台风降水前的大风对各种气溶胶(含海盐、非海盐气溶胶)的清除作用非常显著,而台风降水期间PM_(2.5)中的海盐气溶胶浓度呈现快速上升趋势,最大浓度可达4.39μg·m^(-3).台风降水期间的海盐气溶胶也呈现出一定的老化状态,氯损耗平均值为32.20%,海盐气溶胶的老化程度低于台风降水前和台风降水后的老化程度.尽管台风降水时海盐气溶胶的贡献率有显著增加,气溶胶海洋属性加强,但总体而言海盐气溶胶对深圳地区PM_(2.5)化学组分的贡献非常低.
Typhoon is a synoptic system initiated and developed over ocean surface. Its impact on sea-salt aerosols in coastal cities are therefore of great interest. Based on MARGA ( Monitoring Instrument for Aerosols and Gases) observation data at Zhuzilin atmospheric composition station of Shenzhen, this study investigated the impacts of the 17th typhoon "NESAT" on sea salt aerosols (SSA) in PM2.5. It was found that aerosols concentration had an obvious increase under the influence of downward flow in typhoon periphery area. The strong winds before typhoon precipitation could effectively clear away secondary inorganic aerosols (SIA) and SSA. During the typhoon precipitation period, the mass concentration of SSA increased significantly with a maximum concentration of 4.39 ~g.m-3. SSA in typhoon precipitation period showed a certain aging state with chlorine loss of 32.20%, and the aging degree during typhoon precipitation period was less than those before and after typhoon precipitation. Although the proportions of SSA had an obvious increase during typhoon precipitation stage and the marine properties of aerosols had been more apparent, the contribution of SSA to PM2.5 was still very low in Shenzhen.