An Assessment of the Role of Natural and Anthropogenic CCN on Droplet Size Distributions in Marie Stratus in the North Atlantic

自然和人为 CCN 对北大西洋玛丽层云液滴尺寸分布的作用评估

• 批准号: 9408660
• 负责人: Randolph Borys
• 金额: $ 35.67万
• 依托单位: Nevada System of Higher Education, Desert Research Institute
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1994
• 资助国家: 美国
• 起止时间: 1994-09-15 至 1998-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9408660&HistoricalAwards=false
• 关键词: Assessment; Role; Natural; Anthropogenic; CCN

This pilot field experiment will determine the effects of variations in natural and anthropogenic cloud condensation nuclei (CCN) on marine stratus cloud droplet size distributions in the Canary Islands. The hypothesis to be tested is that increases in CCN numbers, caused by transport of anthropogenic and natural aerosols from Europe and Africa, contrasted to the natural marine situation, will cause a systematic shift to smaller droplet sizes. Although previous work has demonstrated that anthropogenic aerosols have affected cloud microphysics, in case studies, such effects have not been shown to be significant climatologically on a global scale, nor have specific sources of CCN been identified in a remote region. To justify the assertion that the interaction between pollution aerosols and clouds is altering climate, ie., to demonstrate the Twomey Effect, it is necessary to show that a significant portion of the observed variance of the cloud droplet size distribution under background conditions is caused by pollution-derived CCN. This experiment will be conducted at Tenerife in the Canary Islands, where wide variations in natural and anthropogenic CCN are expected, where an existing AEROCE sampling station is located, in the region where the ACE-2 (Aerosol Characterization Experiment) is planned. Marine boundary-layer stratus clouds will be sampled near could base at a ground-based, elevated site. The droplet number and size distribution will be monitored continuously using a PMS- CSASP-100-HV probe (2 to 95 um dia.), and discrete droplet samples will be collected for detailed chemical analysis. The cloud-water chemistry will be used as a surrogate for the chemical composition of the pre-cloud CCN. The relative effects of anthropogenic and natural sources on variations in droplet size distributions will be identified using receptor modeling. Aerosol chemistry from the AEROCE Izania Observatory (2600m) will be compared with the cloud chemistry of m arine stratus.

这个试验性的现场实验将确定自然和人为云凝结核（CCN）的变化对加那利群岛海洋层云云滴大小分布的影响。 有待检验的假设是，与自然海洋情况相比，来自欧洲和非洲的人为和自然气溶胶的输送造成的云凝结核数量的增加将导致系统性地向较小的液滴尺寸转变。 虽然以前的工作已经表明，人为气溶胶影响了云的微物理，在个案研究中，这种影响并没有被证明是在全球范围内的气候显着，也没有在偏远地区的云凝结核的具体来源被确定。 为了证明污染气溶胶和云之间的相互作用正在改变气候的说法，为了证明托米效应，有必要表明，在背景条件下观测到的云滴尺寸分布的方差的很大一部分是由污染引起的云凝结核引起的。 这项实验将在加那利群岛的特内里费岛进行，预计那里的自然和人为云凝结核会有很大的变化，那里有一个现有的AEROCE采样站，计划进行ACE-2（气溶胶特性实验）的区域。 海洋边界层层云将在靠近基地的地面高架站点进行采样。 将使用PMS-CSASP-100-HV探头（直径2 - 95 μ m）连续监测液滴数量和尺寸分布，并收集离散的液滴样品用于详细的化学分析。 云水化学将被用作云前云凝结核化学成分的替代物。 人为和自然源对液滴尺寸分布变化的相对影响将使用受体模型来确定。 AEROCE Izania天文台（2600米）的气溶胶化学将与海洋层云的云化学进行比较。