Ocean flux of salt, sulfate, and organic components to atmospheric aerosol
Ocean flux of salt, sulfate, and organic components to atmospheric aerosol
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DOI：
10.1016/j.earscirev.2023.104364
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发表时间：
2023-03-15
影响因子：
12.1
通讯作者：
Quinn，Patricia K.
中科院分区：
文献类型：
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作者：
Russell，Lynn M.;Moore，Richard H.;Quinn，Patricia K.
海洋通过两种不同的物理机制对大气中的气溶胶颗粒作出贡献：第一种是产生海洋喷雾气溶胶（SSA），第二种是排放气体，这些气体冷凝产生二次海洋气溶胶（SMA）。这些气溶胶排放物包括三种类型的化合物：盐颗粒占质量的90%以上，其中大多数干直径>1 μm;硫酸盐颗粒大多<0.5 μm，通常构成数量最多，对云的影响最大;有机组分包括种类最多的化合物，对云的影响最不确定。预计大多数SSA颗粒是由气泡形成的，作为膜滴，其干燥直径<1 μm，并且是由拍打破裂的气泡形成的，尽管>1 μm的膜滴可以通过韧带断裂形成。SMA颗粒包括海洋生物源气体排放的贡献，包括二甲基硫醚（DMS），异戊二烯，胺和单萜。海洋颗粒物在大气中的作用因地区和季节而异，但由于海洋来源的<1微米颗粒物在大气中的浓度通常比大陆来源的浓度小得多，因此它们对大陆来源有限的地区的气候影响最大。大多数量化全球SSA和SMA排放的努力都依赖于全球模型，其中海洋气溶胶源的表示受到少量现场测量的限制。基于卫星的粗颗粒和海洋气溶胶光学厚度的反演提供了几乎全球的覆盖范围，这与同时发生的风速、白浪和大于1微米颗粒的生物生产力有关。目前SSA通量的最佳估计值为5000 Tg/yr，通过将<1 μm SSA颗粒近似为SSA通量的10%（含7%有机碳），将> 1 μm颗粒近似为SSA通量的90%（不含有机碳），可将SSA相关碳通量计算为35 TgC/yr。据估计，SMA以DMS的形式贡献0.6 TgC/年，以胺的形式贡献0.6 TgC/年，以及来自异戊二烯和单萜的额外痕量，总计<2 TgC/年。由于有限的观测限制SSA和SMA的全球估计，海洋通量的气溶胶和气溶胶前体可能会有两个以上的数量级。需要额外观测约束的关键未决问题包括>1 μm SSA质量尺寸分布的可变性、SSA和SMA对<0.5 μ m粒子数浓度的相对贡献以及可能控制这些<0.5 μm粒子浓度的区域和季节因素。
The oceans contribute to aerosol particles in the atmosphere through two different physical mechanisms: first by the production of sea spray aerosol (SSA), and second by emitting gases that condense to produce secondary marine aerosol (SMA). These aerosol emissions include three types of chemical compounds: salt particles account for >90% of the mass, most of which is >1 μm dry diameter; sulfate particles are mostly <0.5 μm, typically constituting most of the number and the largest impacts on clouds; organic components include the greatest variety of compounds and the most uncertain effects on clouds. Most SSA particles are expected to form from bubbles as film drops that are <1 μm dry diameter and form from flapping bursting bubbles, although >1 μm film drops can form by ligament fragmentation. SMA particles include contributions from marine biogenic gas emissions, including dimethylsulfide (DMS), isoprene, amines, and monoterpenes. The role of particles from the ocean in the atmosphere varies by region and by season, but since atmospheric concentrations of ocean-derived <1 μm particles are typically much smaller than the concentrations of their continental counterparts, they have the largest impacts on climate in regions where continental sources are limited. Most efforts to quantify global SSA and SMA emissions rely on global models, where representations of marine aerosol sources are constrained by a small number of field measurements. Satellite-based retrievals of coarse and marine aerosol optical depth provide near global coverage that has been linked to coincident wind speed, whitecaps, and biological productivity for >1 μm particles. The current best estimate of SSA flux of 5000 Tg/yr can be used to calculate SSA-related carbon flux as 35 TgC/yr, by approximating <1 μm SSA particles as 10% of SSA flux with 7% organic carbon and > 1 μm particles as 90% of SSA flux with no organic carbon. SMA is estimated to contribute 0.6 TgC/yr as DMS, 0.6 TgC/yr as amines, and an additional trace amount from isoprene and monoterpenes for a total of <2 TgC/yr. Because of the limited availability of observations to constrain SSA and SMA global estimates, oceanic fluxes to aerosol and aerosol precursors could vary by over two orders of magnitude. Key open questions that require additional observational constraints include the variability in >1 μm SSA mass size distributions, the relative contributions of SSA and SMA to number concentrations of particles <0.5 μm, and the regional and seasonal factors that may control these <0.5 μm particle concentrations.