New particle formation in the free troposphere: A question of chemistry and timing
New particle formation in the free troposphere: A question of chemistry and timing
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DOI：
10.1126/science.aad5456
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发表时间：
2016-05-27
期刊：
影响因子：
56.9
通讯作者：
Baltensperger, U.
中科院分区：
文献类型：
--
作者：
Bianchi, F.;Trostl, J.;Baltensperger, U.
新粒子形成（NPF）是超过一半的大气云凝结核的来源，从而影响云的性质和地球的能量平衡。与行星边界层不同，自由对流层中NPF的观测很少。我们提供的观测证据表明，在高海拔地区，NPF主要是通过高度氧化的分子（HOM）的冷凝，除了发生通过硫酸氨成核。中性成核比离子诱导成核快10倍以上，并且生长速率取决于尺寸。NPF被限制在空气质量与行星边界层接触后的1至2天的时间窗口内;这与有机化合物氧化形成HOM所需的时间有关。这些发现需要改进大气模式中的NPF参数化。
New particle formation (NPF) is the source of over half of the atmosphere's cloud condensation nuclei, thus influencing cloud properties and Earth's energy balance. Unlike in the planetary boundary layer, few observations of NPF in the free troposphere exist. We provide observational evidence that at high altitudes, NPF occurs mainly through condensation of highly oxygenated molecules (HOMs), in addition to taking place through sulfuric acid-ammonia nucleation. Neutral nucleation is more than 10 times faster than ion-induced nucleation, and growth rates are size-dependent. NPF is restricted to a time window of 1 to 2 days after contact of the air masses with the planetary boundary layer; this is related to the time needed for oxidation of organic compounds to form HOMs. These findings require improved NPF parameterization in atmospheric models.