Cloud chamber experiments on the origin of ice crystal complexity in cirrus clouds
Cloud chamber experiments on the origin of ice crystal complexity in cirrus clouds
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DOI：
10.5194/acp-16-5091-2016
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发表时间：
2015-11
影响因子：
6.3
通讯作者：
M. Schnaiter;E. Järvinen;P. Vochezer;A. Abdelmonem;R. Wagner;O. Jourdan;G. Mioche;V. Shcherbakov
中科院分区：
文献类型：
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作者：
M. Schnaiter;E. Järvinen;P. Vochezer;A. Abdelmonem;R. Wagner;O. Jourdan;G. Mioche;V. Shcherbakov
抽象的。这项研究报告了小规模冰晶复杂性的起源及其对卷云角光散射特性的影响。云模拟实验在卡尔斯鲁厄理工学院（KIT）的AIDA（大气中的气溶胶相互作用和动力学）云室进行。应用一种新的实验程序，在规定的过饱和和亚饱和冰条件下以及-40至-60°C范围内的温度下生长和升华冰粒。实验针对通过均质和异质初始成核生成的冰云进行。小规模冰晶的复杂性是通过最新版本的小冰探测器 (SID-3) 对空间分辨单粒子光散射图案的测量得出的。研究发现，高晶体复杂性主导着模拟云的微观物理，并且这种复杂性的程度取决于晶体生长过程中可用的水蒸气。研究发现，在均匀初始冰成核的情况下，小规模晶体的复杂性受到未冻结的 H2SO4 / H2O 残留物的影响。模拟冰云的角光散射函数由目前可用的两种机载极地浊度计测量：Laboratoire de Meterologie et Physique (LaMP) 的极地浊度计 (PN) 探头和 KIT 的粒子习惯成像和极地散射 (PHIPS-HALO) 探头。测得的散射函数在侧向和后向散射方向上无特征且平坦。研究发现，这些函数对典型大气条件下生长的冰云的小尺度晶体复杂性的敏感性相当低。这些结果对卷云的微物理特性以及通过这些云的辐射传输具有影响。
Abstract. This study reports on the origin of small-scale ice crystal complexity and its influence on the angular light scattering properties of cirrus clouds. Cloud simulation experiments were conducted at the AIDA (Aerosol Interactions and Dynamics in the Atmosphere) cloud chamber of the Karlsruhe Institute of Technology (KIT). A new experimental procedure was applied to grow and sublimate ice particles at defined super- and subsaturated ice conditions and for temperatures in the −40 to −60 °C range. The experiments were performed for ice clouds generated via homogeneous and heterogeneous initial nucleation. Small-scale ice crystal complexity was deduced from measurements of spatially resolved single particle light scattering patterns by the latest version of the Small Ice Detector (SID-3). It was found that a high crystal complexity dominates the microphysics of the simulated clouds and the degree of this complexity is dependent on the available water vapor during the crystal growth. Indications were found that the small-scale crystal complexity is influenced by unfrozen H2SO4 / H2O residuals in the case of homogeneous initial ice nucleation. Angular light scattering functions of the simulated ice clouds were measured by the two currently available airborne polar nephelometers: the polar nephelometer (PN) probe of Laboratoire de Meterologie et Physique (LaMP) and the Particle Habit Imaging and Polar Scattering (PHIPS-HALO) probe of KIT. The measured scattering functions are featureless and flat in the side and backward scattering directions. It was found that these functions have a rather low sensitivity to the small-scale crystal complexity for ice clouds that were grown under typical atmospheric conditions. These results have implications for the microphysical properties of cirrus clouds and for the radiative transfer through these clouds.