春季黄海边界层内海盐细粒子氯亏损及混合状态研究

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(AGE-Asia中NCAR C-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...

Chloride depletion and mixing state of fine sea salt particles in the atmospheric boundary layer of the Yellow Sea in spring

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.