The potential impacts of pollution on a nondrizzling stratus deck : Does aerosol number matter more than type?
The potential impacts of pollution on a nondrizzling stratus deck : Does aerosol number matter more than type?
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污染对非毛毛雨层云甲板的潜在影响：气溶胶数量比类型更重要吗？
DOI：
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发表时间：
2008
期刊：
影响因子：
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通讯作者：
C. Jeffery
中科院分区：
文献类型：
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作者：
M. Andrejczuk;J. Reisner;B. Henson;M. Dubey;C. Jeffery
[1]本文将给出一个云解析模式的结果，该模式可以有效地研究气溶胶对非毛毛雨层云的影响。由于该模式在拉格朗日框架中跟踪气溶胶和云滴，它不会受到与平流有关的数值误差的影响，而且与大多数欧拉方法不同，该方法可以跟踪云在网格单元中移动时的边界。在说明了模式再现各种观测到的云统计数据的能力后，如来自DYCOMS-II现场计划的云水混合比和平均云滴半径，将重点介绍模式评估气溶胶数量和组成变化对层状层的影响的能力。具体地说，通过使用适用于可溶、不溶或两种类型气溶胶的混合物以及某些极端气溶胶状态(即，大多数气溶胶是疏水的碳气溶胶)的激活曲线，考察了限制情况，以限制它们对云的影响。然而，尽管这些情况可能有些极端，但它们偶尔也会发生在大气中，例如大型船只的顺风向海洋层状场或城市地区。不出所料，这些模拟的结果支持了之前的船舶航迹观测，即随着气溶胶数量的增加，云滴数量浓度增加，而云滴半径减少。然而，这些模拟也表明，云滴数浓度和气溶胶数浓度之间的相关性可能不仅是气溶胶数浓度的函数，而且还与气溶胶类型和/或云动力学有关。
[1] In this paper results from a cloud-resolving model that can efficiently examine the impact of aerosol on nondrizzling stratus clouds will be shown. Because the model tracks aerosol and cloud droplets in a Lagrangian framework, it does not suffer from numerical errors associated with advection, and unlike most Eulerian approaches, the method can track cloud boundaries as they move across a grid cell. After illustrating the capability of the model to reproduce various observed cloud statistics such as the cloud water mixing ratio and the mean cloud droplet radius from the DYCOMS-II field program, the ability of the model to assess the impact of changes in aerosol number and composition on a stratus deck will be highlighted. Specifically, by using activation curves appropriate for soluble, insoluble, or a mixture of both types of aerosol and for certain extreme aerosol regimes, i.e., a majority of the aerosol are hydrophobic carbon aerosol, limiting situations were examined to bound their impact on clouds. However, though these situations may be somewhat extreme, they could occasionally occur in the atmosphere, e.g., an oceanic stratus field downwind of a large ship or an urban area. Not unexpectedly, results from these simulations support previous ship track observations that for increasing aerosol numbers, cloud droplet number concentrations increase, whereas cloud droplet radii decrease. However, these simulations also suggest that the correlation between cloud droplet number concentration and aerosol number concentration may be not only a function of aerosol number concentration but also aerosol types and/or cloud dynamics.