为了解海盐气溶胶和亚洲出流污染物的相互影响,对2001年春季黄海边界层内观测的气溶胶细粒子可溶离子浓度(ACE-Asia中NCARC-130飞机航测)进行了研究.所分析的6个航段(航段1~航段6)都位于黄海中部(124.0°E~125.1°E,34.3°N~36.4°N)的大气边界层内.离子摩尔比和相关分析表明,在所分析的几次飞行测量中,气溶胶中Na+来自海盐;氯亏损分析表明,航段1、2中存在氯富集,而航段3、4、5、6中海盐细粒子都存在氯亏损的现象,航段平均氯亏损分别为4.2、5.1、2.9和8.4nmol.m-3,亚洲出流携带的人为排放氯离子造成了氯富集现象,而海盐与输送的酸性气体发生非均相反应则造成了氯亏损,黄海海盐气溶胶具有改变东亚大陆向下游输送污染物化学成分的能力.根据内部混合气溶胶的形成机制分析,提出判断海盐气溶胶细粒子混合状态以及估算内部混合比的间接方法,如果海盐气溶胶存在氯亏损,那么其处于内部混合状态,可用氯亏损的比例估算海盐细粒子的内部混合比.该方法表明航段3、4、5和6中都有内部混合的海盐细粒子,航段平均内部混合比分别为54%、44%、33%和84%.除了反应时间外,还应有多个因子影响海盐气溶胶氯亏损程度以及海盐细粒子混合状态和内部混合比.
In order to understand the interaction between sea salt aerosol over the Yellow Sea and the pollutants in the Asia outflow,the fine particles were observed with a C130 airplane of NCAR as part of ACE-Asia in spring of 2001 in the atmospheric boundary layer (ABL) of the Yellow Sea. There were six legs analyzed in this paper (defined as leg 1,leg 2,leg 3,leg 4,leg 5,and leg 6) located all in the ABL of the central parts of the Yellow sea (124.0°E~125.1°E,34.3°N~36.4°N). The mole ratio and correlation analyses of soluble ion concentrations in the fine particles show that the sodium ion is from sea salt. Chloride depletion analyses indicate that the chloride enrichment in fine sea salt particles is found in the leg 1 and 2,and the chloride depletion is observed in leg 3,4,5,and 6. The leg averaged concentration of chloride depletion is 4.2,5.1,2.9,and 8.4 nmol·m-3,respectively. The chloride enrichment may be caused by anthropogenic chloride ion in the Asia outflow. The chloride depletion is attributed to reaction between the sea salt aerosol and the acid gases transported from East Asia. The sea salt over the Yellow Sea can change the components of pollutants transported from East Asia. Based on the formation mechanism of internally mixed aerosol,an indirect method is developed to judge the mixing state of fine sea salt particles and calculate the internal mixing ratio. The fine sea salt particles are internally mixed when chloride depletion occurs,and the ratio of the internal mixture can be estimated from the chloride depletion ratio. According to the method,there are internally mixed fine sea salt particles observed in the leg 3,4,5,and 6 with leg averaged ratio of internal mixture being 54%,44%,33%,and 84%,respectively. Besides reaction time,there should be other factors that can influence the chloride depletion in sea salt,and the mixing state and mixing ratio of fine sea salt particles.