Experimental investigation of homogeneous freezing of sulphuric acid particles in the aerosol chamber AIDA
Experimental investigation of homogeneous freezing of sulphuric acid particles in the aerosol chamber AIDA
复制标题
气溶胶室AIDA中硫酸颗粒均匀冷冻的实验研究
DOI：
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发表时间：
2002
期刊：
影响因子：
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通讯作者：
U. Schurath
中科院分区：
文献类型：
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作者：
O. Möhler;O. Stetzer;S. Schaefers;C. Linke;M. Schnaiter;R. Tiede;H. Saathoff;M. Krämer;A. Mangold;P. Budz;P. Zink;J. Schreiner;K. Mauersberger;W. Haag;B. Kärcher;U. Schurath
在卡尔斯鲁厄Forschungszentrum Karlsruhe的气溶胶室AIDA （aerosol Interactions and Dynamics in Atmosphere）中研究了过冷H2SO4/H2O溶液液滴的均匀冻结，在189 ~ 235 K的温度范围内进行了24次冻结实验，气溶胶颗粒的直径范围为0.05 ~ 1µm。单个实验在均匀温度下开始，冰的饱和比在0.9到0.95之间。利用机械泵进行膨胀冷却，在室内模拟了高达2.8 K min 1的云冷却速率。根据冷却速率和起始温度的不同，在膨胀时间约为1至10分钟后，会超过冻结阈值相对湿度。用三种独立的方法测量了冰形成的开始，它们之间表现出很好的一致性。在结冰开始时测得的冰饱和比从231 K时的约1.4增加到189 K时的约1.75。实验数据集包括热力学参数以及气溶胶的物理和化学分析，为微物理模型的应用提供了良好的基础。
The homogeneous freezing of supercooled H2SO4/H2O solution droplets was investigated in the aerosol chamber AIDA (Aerosol Interactions and Dynamics in the Atmosphere) of Forschungszentrum Karlsruhe. 24 freezing experiments were performed at temperatures between 189 and 235 K with aerosol particles in the diameter range 0.05 to 1µm. Individual experiments started at homogeneous temperatures and ice saturation ratios between 0.9 and 0.95. Cloud cooling rates up to 2.8 K min 1 were simulated dy- namically in the chamber by expansion cooling using a me- chanical pump. Depending on the cooling rate and starting temperature, freezing threshold relative humidities were ex- ceeded after expansion time periods between about 1 and 10 min. The onset of ice formation was measured with three independent methods showing good agreement among each other. Ice saturation ratios measured at the onset of ice for- mation increased from about 1.4 at 231 K to about 1.75 at 189 K. The experimental data set including thermodynamic parameters as well as physical and chemical aerosol analysis provides a good basis for microphysical model applications.