Relationship between hygroscopicity and cloud condensation nuclei activity for urban aerosols in Tokyo
Relationship between hygroscopicity and cloud condensation nuclei activity for urban aerosols in Tokyo
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DOI：
10.1029/2005jd006980
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发表时间：
2006-12-07
影响因子：
4.4
通讯作者：
Kondo, Yutaka
中科院分区：
文献类型：
--
作者：
Mochida, Michihiro;Kuwata, Mikinori;Kondo, Yutaka
根据科勒理论，大气气溶胶颗粒的吸湿性是调节其云凝结核（CCN）活动的关键因素。在这里，我们使用与 CCN 计数器串联的吸湿性串联微分迁移率分析仪 (HTDMA) 研究了城市气溶胶颗粒的吸湿性和 CCN 活性之间的关系。 HTDMA-CCNC系统于2004年11月10日至17日在东京都市中心附近运行。对于干燥迁移直径为30-200 nm的气溶胶颗粒，获得了0.22-1.3%过饱和度下CCN与凝结核(CN)的比率，作为83%和89%RH下颗粒吸湿性的函数。研究发现，吸湿性较高的颗粒比相同尺寸的吸湿性较小的颗粒具有更高的 CCN 活性，这表明吸湿性是调节 CCN 活性的关键因素。使用气溶胶质谱仪同时测量颗粒的化学成分。研究发现它们与 CCN 活性以及吸湿性密切相关。将测得的 CCN-吸湿性关系与科勒理论预测的关系进行比较。结果表明，CCN 活性可能受到有机物引起的表面张力变化、过饱和条件下水溶性有机物的溶解/离解或有机物与无机盐的不同非理想性的干扰。这些与有机物相关的因素对于 CCN 活动以及大气中的微物理云过程可能很重要。
As described by the Kohler theory, the hygroscopicity of atmospheric aerosol particles is a key factor regulating their cloud condensation nuclei (CCN) activity. Here we investigated the relationship between hygroscopicity and CCN activity for urban aerosol particles using a hygroscopicity tandem differential mobility analyzer (HTDMA) coupled in series to a CCN counter. The HTDMA-CCNC system was operated near the center of the Tokyo metropolitan area from 10 to 17 November 2004. For aerosol particles whose dry mobility diameters were 30-200 nm, the ratios of CCN to condensation nuclei (CN) at 0.22-1.3% supersaturation were obtained as a function of particle hygroscopicity at 83 and 89% RH. More-hygroscopic particles were found to be more CCN active than less-hygroscopic particles of the same size, indicating that hygroscopicity is a critical factor regulating CCN activity. The chemical compositions of particles were simultaneously measured using an aerosol mass spectrometer. They were found to relate closely to CCN activity as well as to the hygroscopicity. The measured CCN-hygroscopicity relationships were compared to those predicted by Kohler theory. The results suggest that CCN activity is possibly perturbed by changes in surface tension due to organics, dissolution/dissociation of water-soluble organics under supersaturation conditions, or different nonideality of organics from inorganic salts. These factors associated with organics are potentially important for CCN activity and thus microphysical cloud processes in the atmosphere.