Sanchez Kevin J, Chen Chia-Li, Russell Lynn M, Betha Raghu, Liu Jun, Price Derek J, Massoli Paola, Ziemba Luke D, Crosbie Ewan C, Moore Richard H, Müller Markus, Schiller Sven A, Wisthaler Armin, Lee Alex K Y, Quinn Patricia K, Bates Timothy S, Porter Jack, Bell Thomas G, Saltzman Eric S, Vaillancourt Robert D, Behrenfeld Mike J
Scripps Institution of Oceanography, University of California, San Diego, La Jolla, CA, USA.
Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO, USA.
Sci Rep. 2018 Feb 19;8(1):3235. doi: 10.1038/s41598-018-21590-9.
Biogenic sources contribute to cloud condensation nuclei (CCN) in the clean marine atmosphere, but few measurements exist to constrain climate model simulations of their importance. The chemical composition of individual atmospheric aerosol particles showed two types of sulfate-containing particles in clean marine air masses in addition to mass-based Estimated Salt particles. Both types of sulfate particles lack combustion tracers and correlate, for some conditions, to atmospheric or seawater dimethyl sulfide (DMS) concentrations, which means their source was largely biogenic. The first type is identified as New Sulfate because their large sulfate mass fraction (63% sulfate) and association with entrainment conditions means they could have formed by nucleation in the free troposphere. The second type is Added Sulfate particles (38% sulfate), because they are preexisting particles onto which additional sulfate condensed. New Sulfate particles accounted for 31% (7 cm) and 33% (36 cm) CCN at 0.1% supersaturation in late-autumn and late-spring, respectively, whereas sea spray provided 55% (13 cm) in late-autumn but only 4% (4 cm) in late-spring. Our results show a clear seasonal difference in the marine CCN budget, which illustrates how important phytoplankton-produced DMS emissions are for CCN in the North Atlantic.
生物源对清洁海洋大气中的云凝结核（CCN）有贡献，但用于约束其重要性的气候模型模拟的测量数据很少。除了基于质量的估计盐颗粒外，单个大气气溶胶颗粒的化学成分在清洁海洋气团中显示出两种含硫酸盐颗粒。这两种硫酸盐颗粒都缺乏燃烧示踪剂，并且在某些条件下与大气或海水中的二甲基硫（DMS）浓度相关，这意味着它们的来源主要是生物源。第一种类型被确定为新硫酸盐，因为它们的硫酸盐质量分数大（63%硫酸盐）且与夹卷条件有关，这意味着它们可能是在自由对流层中通过成核形成的。第二种类型是添加硫酸盐颗粒（38%硫酸盐），因为它们是已有颗粒，额外的硫酸盐在其上凝结。在深秋和晚春，新硫酸盐颗粒在0.1%过饱和度下分别占CCN的31%（7厘米）和33%（36厘米），而在深秋海沫提供了55%（13厘米），但在晚春仅提供了4%（4厘米）。我们的结果表明海洋CCN预算存在明显的季节差异，这说明了浮游植物产生的DMS排放对北大西洋CCN的重要性。
