Mass-particle size distributions of atmospheric dust and the dry deposition of dust to the remote ocean
Mass-particle size distributions of atmospheric dust and the dry deposition of dust to the remote ocean
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DOI：
10.1029/97jd00796
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发表时间：
1997-07-20
影响因子：
4.4
通讯作者：
Duce, RA
中科院分区：
文献类型：
--
作者：
Arimoto, R;Ray, BJ;Duce, RA
收集和分析了粒径分离的矿物气溶胶样品，探讨了粉尘颗粒的质量粒径分布（MSDs）与大气中粉尘负荷之间的关系，并利用这些数据评估了粉尘的MSDs在运输过程中的变化，特别是对干沉降的相关影响。从遥远的北大西洋三个地点收集的样本中，铝或钪的大气尘埃浓度高于在北太平洋上乘坐R/V莫阿纳波号巡航时收集的样本。然而，北太平洋样本的质量中值直径（MMDs）平均更大（类似于3 μ m，而类似于2 μ m的空气动力学等效直径），而且比北大西洋样本的变化更大；这种差异归因于北太平洋的潮湿条件和颗粒聚集。此外，对于所有样品的集合，质量粒度分布的几何标准偏差（类似于用于表征沉积物质的分选值）倾向于与质量中位数直径呈反比和非线性变化。模型导出的样品干沉积速度与粉尘浓度或MMDs的关系最弱。然而，两个样本子集的干沉积速度与分布的几何标准差相关；这进一步证明，通过干沉积的尘埃质量通量可以由相对一小部分空气动力学大颗粒控制。
Size-separated mineral aerosol samples were collected and analyzed to investigate the relationships between the mass-particle size distributions (MSDs) of dust particles and the dust loadings in the atmosphere, The data also were used to assess the changes in the MSDs of dust in relation to transport processes and especially the associated effects on dry deposition. Atmospheric dust concentrations, as indicated by aluminum or scandium, in samples collected from three sites in the remote North Atlantic were higher than those in samples collected during a cruise in the North Pacific on board the R/V Moana Wave. However, the mass median diameters (MMDs) for the North Pacific samples were both larger on average (similar to 3 mu m versus similar to 2 mu m aerodynamic equivalent diameter) and more variable than those from the North Atlantic; this difference was attributed to wet conditions and particle aggregation over the North Pacific. In addition, for the ensemble of all samples the geometric standard deviations of the mass-particle size distributions, which are analogous to the sorting values used to characterize sedimentary materials, tended to vary inversely and nonlinearly with the mass median diameters. Model-derived dry deposition velocities for the samples were at most weakly related to either the dust concentrations or the MMDs. However, the dry deposition velocities for two subsets of samples were correlated with the geometric standard deviations of the distributions; this is further evidence that the mass flux of dust via dry deposition can be controlled by a relatively small fraction of aerodynamically large particles.