Sensitivity of cloud condensation nuclei to regional changes in dimethyl-sulphide emissions
Sensitivity of cloud condensation nuclei to regional changes in dimethyl-sulphide emissions
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DOI：
10.5194/acp-13-2723-2013
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发表时间：
2012-10
影响因子：
6.3
通讯作者：
M. Woodhouse;G. Mann;K. Carslaw;O. Boucher
中科院分区：
文献类型：
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作者：
M. Woodhouse;G. Mann;K. Carslaw;O. Boucher
抽象的。海洋浮游植物产生的二甲硫醚 (DMS) 的大气氧化是海洋硫酸盐气溶胶的重要来源。 DMS 被提议通过云特性的变化来调节气候，尽管最近的研究表明，目前全球云凝结核 (CCN) 浓度对 DMS 总排放通量的依赖性很弱。在这里，我们使用全球气溶胶微物理模型来研究当不同海洋区域的 DMS 排放发生变化时 CCN 的产生效率。我们发现，全球每单位质量硫排放的 CCN 产量变化超过 20 倍，具体取决于应用海洋 DMS 排放通量变化的位置。 CCN生产效率的变化取决于CCN生产工艺（DMS氧化、SO 2 氧化、成核和生长）最高效和去除工艺（沉积）最效率最低的情况。分析表明，SO 2 的水相氧化产生的气溶胶硫酸盐限制了可用于成核和凝结生长的H 2 SO 4 的量，因此抑制了CCN的形成，导致CCN对DMS排放变化的响应较弱。我们的结果表明，过去和未来 DMS 排放空间分布的变化（通过浮游植物种群或风速模式的变化）可能比生物生产力的净增长对气候产生更强的控制作用。
Abstract. The atmospheric oxidation of dimethyl-sulphide (DMS) derived from marine phytoplankton is a significant source of marine sulphate aerosol. DMS has been proposed to regulate climate via changes in cloud properties, though recent studies have shown that present-day global cloud condensation nuclei (CCN) concentrations have only a weak dependence on the total emission flux of DMS. Here, we use a global aerosol microphysics model to examine how efficiently CCN are produced when DMS emissions are changed in different marine regions. We find that global CCN production per unit mass of sulphur emitted varies by more than a factor of 20 depending on where the change in oceanic DMS emission flux is applied. The variation in CCN production efficiency depends upon where CCN production processes (DMS oxidation, SO 2 oxidation, nucleation and growth) are most efficient and removal processes (deposition) least efficient. The analysis shows that the production of aerosol sulphate through aqueous-phase oxidation of SO 2 limits the amount of H 2 SO 4 available for nucleation and condensational growth and therefore suppresses CCN formation, leading to the weak response of CCN to changes in DMS emission. Our results show that past and future changes in the spatial distribution of DMS emissions (through changes in the phytoplankton population or wind speed patterns) could exert a stronger control on climate than net increases in biological productivity.