Particle Habit Imaging Using Incoherent Light: A First Step toward a Novel Instrument for Cloud Microphysics
Particle Habit Imaging Using Incoherent Light: A First Step toward a Novel Instrument for Cloud Microphysics
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DOI：
10.1175/2011jtecha1445.1
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发表时间：
2011-04
影响因子：
2.2
通讯作者：
R. Schon;M. Schnaiter;Z. Ulanowski;C. Schmitt;S. Benz;O. Möhler;Steffen Vogt;R. Wagner;U. Schur
中科院分区：
文献类型：
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作者：
R. Schon;M. Schnaiter;Z. Ulanowski;C. Schmitt;S. Benz;O. Möhler;Steffen Vogt;R. Wagner;U. Schur
研制了新型云粒子仪器粒子习惯成像和极散射（PHIPS）探针的成像单元，用于对大型云室内产生的单个冰粒子进行成像。PHIPS产生单个空中冰晶的图像，用超快闪光灯的白光照射，捕获的最大频率为；5 Hz，通过带显微镜光学元件的电荷耦合器件（CCD）相机。仪器的成像特性是通过六氟硅酸钠晶体冰类似物表征的，该类似物在室温下是稳定的。系统的光学分辨能力为；2毫米。通过使用专用的图像处理和分析算法，可以自动分析冰晶图像的大小和选定的形状参数。PHIPS在卡尔斯鲁厄理工学院云模拟室设施大气气溶胶相互作用与动力学（AIDA）中在2178℃至248℃之间的不同温度下运行，以研究环境条件（即温度和冰饱和比）对冰晶习惯的影响。将PHIPS图像的面积等效尺寸分布与傅里叶变换红外（FTIR）消光光谱的检索结果进行了比较，在较小（约20mm）的情况下，与云粒子成像仪的单粒子数据进行了比较。20毫米)冰粒。两种粒径体系都有很好的一致性。
The imaging unit of the novel cloud particle instrument Particle Habit Imaging and Polar Scattering (PHIPS) probe has been developed to image individual ice particles produced inside a large cloud chamber. The PHIPS produces images of single airborne ice crystals, illuminated with white light of an ultrafast flashlamp, which are captured at a maximum frequency of ;5 Hz by a charge-coupled device (CCD) camera with microscope optics. The imaging properties of the instrument were characterized by means of crystalline sodium hexafluorosilicate ice analogs, which are stable at room temperature. The optical resolving power of the system is ;2 mm. By using dedicated algorithms for image processing and analysis, the ice crystal images can be analyzed automatically in terms of size and selected shape parameters. PHIPS has been operated at the cloud simulation chamber facility Aerosol Interaction and Dynamics in the Atmosphere (AIDA) of the Karlsruhe Institute of Technology at different temperatures between 2178 and 248C in order to study the influence of the ambient conditions, that is, temperature and ice saturation ratio, on ice crystal habits. The area-equivalent size distributions deduced from the PHIPS images are compared with the retrieval results from Fourier transform infrared (FTIR) extinction spectroscopy in case of small (,20 mm) and with single particle data from the cloud particle imager in case of larger (.20 mm) ice particles. Good agreement is found for both particle size regimes.