Cloud properties inferred from bimodal aerosol number distributions
Cloud properties inferred from bimodal aerosol number distributions
复制标题
从双峰气溶胶数量分布推断的云特性
DOI：
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发表时间：
1999
期刊：
影响因子：
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通讯作者：
R. Benner
中科院分区：
文献类型：
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作者：
W. Cantrell;G. Shaw;R. Benner
非降水云层通过将气溶胶颗粒分离成两个种群，在循环通过它们的气溶胶颗粒上留下独特的指纹，这些种群包括在云滴中和不包含在云滴中。这导致气溶胶数分布呈现双峰或双峰特征。如果做了一些合理的假设，就可以从气溶胶的双峰分布中推断出云的微物理性质。我们从北美的五个站收集了1700多个双峰分布，并推断出处理气溶胶粒子的云滴浓度和最大过饱和度。“本底”站平均云滴浓度为10 0~2 0 0 cm−3，污染点云滴浓度高达30 0 0 cm−3，最大过饱和度范围为0.3%~0.1%。云滴浓度和最大过饱和度通常是负相关的。云滴浓度与气溶胶数分布中云处理模式的几何平均直径也呈负相关。通过与云激活的简单模型进行比较，可以理解这两种关系。
Nonprecipitating clouds leave a distinctive fingerprint on the aerosol particles that cycle through them by segregating aerosol particles into two populations, those which are incorporated into cloud droplets and those which are not. This leads to a bimodal or double-peaked character in the aerosol number distribution. If some reasonable assumptions are made, cloud microphysical properties can be inferred from the bimodal aerosol distributions. We have collected over 1700 bimodal distributions from five stations in North America and inferred cloud droplet concentration and maximum supersaturation in the clouds which processed the aerosol particles. Average cloud droplet concentrations are 100–200 cm−3 at “background” stations, while at the polluted site, cloud droplet concentrations were as high as 3000 cm−3. Inferred values of maximum supersaturation ranged from 0.3% at clean sites to 0.1% at the polluted site. Cloud droplet concentration and maximum supersaturation were usually inversely correlated. Cloud droplet concentration and geometric mean diameter of the cloud-processed mode in the aerosol number distribution were also inversely correlated. These two relationships can be understood by comparison with a simple model of cloud activation.