The accommodation coefficient of water molecules on ice – cirrus cloud studies at the AIDA simulation chamber
The accommodation coefficient of water molecules on ice – cirrus cloud studies at the AIDA simulation chamber
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冰上水分子的调节系数——AIDA模拟室的卷云研究
DOI：
10.5194/acp-13-4451-2013
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发表时间：
2012
影响因子：
6.3
通讯作者：
T. Leisner
中科院分区：
文献类型：
--
作者：
J. Skrotzki;P. Connolly;M. Schnaiter;H. Saathoff;O. Möhler;R. Wagner;M. Niemand;V. Ebert;T. Leisner
抽象。卷云及其对地球辐射收支的影响是当前研究的主题。控制卷云冰粒生长的过程是卷云辐射特性的核心。在与卷云相关的温度下，尺寸小于几微米的冰晶的生长受到冰上水分子的适应系数α冰的强烈影响，使该参数与卷云建模相关。然而，实验确定的卷云温度α冰的大小受到几乎三个数量级的不确定性的困扰，并且从卷云数据中获得的α冰值到目前为止缺乏意义。这激发了在云室AIDA（大气中的气溶胶相互作用和动力学）进行的专门实验，以确定在实际卷云冰粒生长条件下，在190 K和235 K之间的卷云相关温度区间内的α冰。实验数据集进行了独立评估与两个模型的方法：第一个依赖于新开发的模型SIGMA（简单的冰增长模型确定阿尔法），第二个在一个既定的模型，ACPIM（气溶胶云降水相互作用模型）。在这两种方法中，对每个AIDA实验所获得的α冰值进行了仔细的不确定性分析。结果表明，在190 ~ 235 K之间，α冰对温度没有明显的依赖性。此外，我们没有发现α冰依赖于冰粒尺寸或水蒸气过饱和度的冰粒小于20 μm和过饱和度高达70%的证据。两个模型的温度平均和综合结果为α冰= 0.7−0.5+0.3，这意味着与α冰=1的假设相比，α冰可能对卷云及其特征只产生很小的影响。对卷云特性的先前计算的影响，例如，在气候模型中，α冰通常选择在0.2-1之间，因此预计可以忽略不计。在任何情况下，我们提供了一个约束良好的α冰，未来卷云模型研究可以依赖。
Abstract. Cirrus clouds and their impact on the Earth's radiative budget are subjects of current research. The processes governing the growth of cirrus ice particles are central to the radiative properties of cirrus clouds. At temperatures relevant to cirrus clouds, the growth of ice crystals smaller than a few microns in size is strongly influenced by the accommodation coefficient of water molecules on ice, αice, making this parameter relevant for cirrus cloud modeling. However, the experimentally determined magnitude of αice for cirrus temperatures is afflicted with uncertainties of almost three orders of magnitude, and values for αice derived from cirrus cloud data lack significance so far. This has motivated dedicated experiments at the cloud chamber AIDA (Aerosol Interactions and Dynamics in the Atmosphere) to determine αice in the cirrus-relevant temperature interval between 190 K and 235 K under realistic cirrus ice particle growth conditions. The experimental data sets have been evaluated independently with two model approaches: the first relying on the newly developed model SIGMA (Simple Ice Growth Model for determining Alpha), the second one on an established model, ACPIM (Aerosol-Cloud-Precipitation Interaction Model). Within both approaches a careful uncertainty analysis of the obtained αice values has been carried out for each AIDA experiment. The results show no significant dependence of αice on temperature between 190 K and 235 K. In addition, we find no evidence for a dependence of αice on ice particle size or on water vapor supersaturation for ice particles smaller than 20 μm and supersaturations of up to 70%. The temperature-averaged and combined result from both models is αice = 0.7−0.5+0.3, which implies that αice may only exert a minor impact on cirrus clouds and their characteristics when compared to the assumption of αice =1. Impact on prior calculations of cirrus cloud properties, e.g., in climate models, with αice typically chosen in the range 0.2–1 is thus expected to be negligible. In any case, we provide a well-constrained αice which future cirrus model studies can rely on.
影响因子：
6.3
作者：
M. Schnaiter;S. Büttner;O. Möhler;J. Skrotzki;M. Vragel;R. Wagner
通讯作者：
M. Schnaiter;S. Büttner;O. Möhler;J. Skrotzki;M. Vragel;R. Wagner
使用新型粒子习性成像和极地散射 (PHIPS) 探头首次对云粒子的形状和光散射特性进行相关测量
影响因子：
3.8
作者：
Abdelmonem A
通讯作者：
Abdelmonem A
影响因子：
6.3
作者：
Connolly P
通讯作者：
Connolly P