A meta-analysis of particle water uptake reconciliation studies
A meta-analysis of particle water uptake reconciliation studies
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DOI：
10.5194/acp-14-11833-2014
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发表时间：
2014-11
影响因子：
6.3
通讯作者：
J. Whitehead;M. Irwin;J. Allan;N. Good;N. Good;G. Mcfiggans
中科院分区：
文献类型：
--
作者：
J. Whitehead;M. Irwin;J. Allan;N. Good;N. Good;G. Mcfiggans
摘要。气溶胶颗粒对水的吸收控制着它们形成云滴的能力，不同的云凝结核（CCN）特性检测技术之间的协调对我们理解这些过程以及测量和预测它们的能力非常重要。在2007年至2013年期间，在广泛的地点尝试了亚饱和和过饱和气溶胶颗粒吸水性测量之间的协调。在不同的项目中，CCN （NCCN）或颗粒吸湿性的导出数的一致性参差不齐，一些数据集显示所有过饱和度的一致性很差，而另一些数据集在至少一些过饱和范围内的误差范围内一致。协调的程度似乎并不取决于进行测量的环境。差异只能归因于每个仪器中气溶胶和气体的化学行为差异，导致生长因子和/或CCN计数低估或高估，尽管较低过饱和度下较差的调和可归因于在这些过饱和度下发现的阈值直径的尺寸分布的不确定性。从单一仪器来看，利用颗粒吸湿性或整个项目平均粒径分布计算的NCCN变异性表明，在大多数实验中，粒径分布的变化比化学成分的变化更敏感。然而，仪器之间的差异表明，随着对测量中涉及的物理过程的理解的提高，对CCN可靠量化的强烈要求。在不了解测量差异的原因的情况下，CCN行为的量化是否有意义是值得怀疑的。
Abstract. Water uptake by aerosol particles controls their ability to form cloud droplets, and reconciliation between different techniques for examining cloud condensation nuclei (CCN) properties is important to our understanding of these processes and our ability to measure and predict them. Reconciliation between measurements of sub-saturated and supersaturated aerosol particle water uptake was attempted at a wide range of locations between 2007 and 2013. The agreement in derived number of CCN (NCCN or particle hygroscopicity was mixed across the projects, with some data sets showing poor agreement across all supersaturations and others agreeing within errors for at least some of the supersaturation range. The degree of reconciliation did not seem to depend on the environment in which the measurements were taken. The discrepancies can only be attributable to differences in the chemical behaviour of aerosols and gases in each instrument, leading to under- or overestimated growth factors and/or CCN counts, though poorer reconciliation at lower supersaturations can be attributed to uncertainties in the size distribution at the threshold diameter found at these supersaturations. From a single instrument, the variability in NCCN calculated using particle hygroscopicity or size distribution averaged across a project demonstrates a greater sensitivity to variation in the size distribution than chemical composition in most of the experiments. However, the discrepancies between instruments indicate a strong requirement for reliable quantification of CCN in line with an improved understanding of the physical processes involved in their measurement. Without understanding the reason for discrepancies in the measurements, it is questionable whether quantification of CCN behaviour is meaningful.