Cloud condensation nuclei activity at Jeju Island, Korea in spring 2005
Cloud condensation nuclei activity at Jeju Island, Korea in spring 2005
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DOI：
10.5194/acp-8-2933-2008
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发表时间：
2008-01-01
影响因子：
6.3
通讯作者：
Matsueda, H.
中科院分区：
文献类型：
--
作者：
Kuwata, M.;Kondo, Y.;Matsueda, H.
我们测量的云凝结核（CCN）的数量浓度和CCN/CN（CN：凝结核）比的大小分布在过饱和度（SS）为0.097，0.27，0.58，和0.97%，韩国济州岛在2005年3月至4月。我们同时测量了PM2.5中的气溶胶无机离子、水溶性有机碳（WSOC）、有机碳（OC）和元素碳（EC）。CCN/CN比随着粒径的增加而增加，并且将CCN/CN=0.5时的直径定义为D-50。D-50表示大气颗粒的活化干直径。SS=0.097%和0.97%时的平均D-50分别为136+/-17 nm和31+/-3 nm。SS=0.097%时D-50的时间变化与水溶性组分（无机离子+ WSOC）的质量分数相关，表明CCN活性的时间变化主要受水溶性组分的变化控制。临界干直径（D-crit）是CCN活化的阈值干直径，由观测到的气溶胶化学成分通过科勒理论计算，用于与D-50进行比较。SS=0.097%时的D-50与计算的D-临界值相关（r（2）=0.48），尽管D-临界值平均比D-50大20-29%。D-50和D-crit之间的系统差异可能是由气溶胶化学成分的尺寸依赖性或水溶性有机化合物混合引起的表面张力降低引起的。该差异对应于根据观察到的颗粒数尺寸分布估计的CCN数浓度的27+/-14%不确定性。
We measured the number concentrations of cloud condensation nuclei (CCN) and the size distributions of CCN/CN (CN: condensation nuclei) ratios at supersaturations (SSs) of 0.097, 0.27, 0.58, and 0.97% at Jeju Island, Korea during March-April 2005. We made simultaneous measurements of aerosol inorganic ions, water-soluble organic carbon (WSOC), organic carbon (OC), and elemental carbon (EC) in PM2.5. The CCN/CN ratios increased with increasing particle diameter, and the diameter at CCN/CN=0.5 was defined as D-50. D-50 represents the activation dry diameter of atmospheric particles. The average D-50 at SS=0.097% and 0.97% was 136+/-17 nm and 31+/-3 nm, respectively. The temporal variation of D-50 at SS=0.097% was correlated with the mass fraction of water-soluble components (inorganic ions + WSOC), indicating that the temporal variation of CCN activity was mainly controlled by changes in the water-soluble components fraction. The critical dry diameter (D-crit), which is the threshold dry diameter for CCN activation, was calculated from the observed aerosol chemical compositions by Kohler theory for comparison with D-50. The D-50 at SS=0.097% was correlated (r(2)=0.48) with calculated D-crit, although D-crit was larger than D-50 by 20-29% on average. The systematic difference between D-50 and D-crit could be caused by the size dependence of the aerosol chemical compositions or surface tension lowering caused by the mixing of water-soluble organic compounds. This difference corresponds to a 27+/-14% uncertainty in the CCN number concentration estimated from the observed particle number size distribution.