Ice nucleation on flame soot aerosol of different organic carbon content
Ice nucleation on flame soot aerosol of different organic carbon content
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不同有机碳含量火焰烟灰气溶胶的冰核
DOI：
10.1127/0941-2948/2005/0055
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发表时间：
2005
影响因子：
1.2
通讯作者：
U. Schurath
中科院分区：
文献类型：
--
作者：
O. Möhler;C. Linke;H. Saathoff;M. Schnaiter;R. Wagner;A. Mangold;M. Krämer;U. Schurath
利用气溶胶气溶胶相互作用和动力学（Aerosol Interactions and Dynamics in the Atmosphere，AIDA）气溶胶室作为中等膨胀云室，研究了有机碳（OC）含量对煤烟气溶胶粒子冰成核特性的影响。OC含量为16%（CS 16）和40%（CS40）的两种不同的碳烟样品用在不同空气/燃料（丙烷）比下操作的CAST（燃烧气溶胶标准）燃烧器产生。在相对于冰的相对湿度增加约30%/min的动态膨胀实验中，CS 16样品在1.45的冰饱和比S in（在207 K的温度下）开始成核冰晶。该值非常接近于在先前的AIDA膨胀实验中研究的涂覆有显著量的硫酸的碳火花发生器烟灰颗粒上的冰成核开始的冰饱和比。在几乎相同的热力学条件下进行的CS40烟灰的第二个实验表明，冰成核开始发生在1.5和1.7之间的S处。冰晶的形成速率至少比CS 16烟灰小两个数量级，即使在冰饱和比高达1.9的值时也是如此，这非常接近于207 K温度下的水饱和度。因此，增加OC的量似乎显著抑制火焰碳烟颗粒上的冰成核。相比之下，类似的膨胀实验与干燥和未经处理的矿物粉尘颗粒（亚利桑那州测试粉尘）在194至241 K的温度范围内显示冰成核发生在低得多的冰饱和比只有1.05至1.15。
The aerosol chamber AIDA (Aerosol Interactions and Dynamics in the Atmosphere) was used as a moderate expansion cloud chamber to investigate the effect of the organic carbon (OC) content on the ice nucleation properties of soot aerosol particles. Two different soot samples with OC contents of 16 % (CS16) and 40 % (CS40) where produced with the CAST (Combustion Aerosol Standard) burner operated at different air/fuel (propane) ratios. In dynamic expansion experiments with about 30 %/min increase of relative humidity with respect to ice, the CS16 sample started to nucleate ice crystals at an ice saturation ratio S in of 1.45 (at a temperature of 207 K). This value is very close to the ice saturation ratio of ice nucleation onset on carbon spark generator soot particles coated with a significant amount of sulphuric acid investigated in previous AIDA expansion experiments. A second experiment with CS40 soot performed at almost identical thermodynamic conditions showed ice nucleation onset to occur at S in between 1.5 and 1.7. The formation rate of ice crystals was at least two orders of magnitude less than for CS16 soot, even at ice saturation ratios up to values of 1.9, which is very close to water saturation at a temperature of 207 K. Therefore, increasing the amount of OC seems to significantly suppress the ice nucleation on flame soot particles. In contrast, similar expansion experiments with dry and untreated mineral dust particles (Arizona test dust) in the temperature range 194 to 241 K showed ice nucleation to occur at much lower ice saturation ratios of only 1.05 to 1.15.