The ice nucleating ability of pollen: Part II. Laboratory studies in immersion and contact freezing modes
The ice nucleating ability of pollen: Part II. Laboratory studies in immersion and contact freezing modes
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DOI：
10.1016/s0169-8095(01)00132-6
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发表时间：
2002-02-01
影响因子：
5.5
通讯作者：
Mitra, SK
中科院分区：
文献类型：
--
作者：
Diehl, K;Matthias-Maser, S;Mitra, SK
对4种花粉在浸泡和接触冷冻条件下的冰核能力进行了室内试验。所选花粉的直径在25和70 μ m之间。实验是在美因茨垂直风洞中进行的，自由悬浮的过冷液滴温度低至-28摄氏度。浸渍冷冻实验进行与滴半径在250和375 μ m之间形成的蒸馏水与限定量的花粉添加。液滴在风洞中自由漂浮，同时过冷。对于接触冷冻实验，允许花粉的短暂爆发与360-Mum半径的自由悬浮的过冷纯水滴碰撞。结果表明，在风洞中，无颗粒空气中的无颗粒水滴在-28 ℃以上的温度下不会冻结，而含有花粉的水滴在-9 ℃的温度下冻结，水滴与花粉碰撞时在-5 ℃或更低的温度下冻结。结合一些细菌，海洋浮游生物和落叶的冰成核能力的早期结果，目前的研究结果证实了生物气溶胶颗粒作为潜在的冰核在相对温暖的温度的重要性。(C)2002 Elsevier Science B. V.保留所有权利。
Laboratory tests were conducted of the ice nucleating ability of four kinds of pollen in the immersion and the contact freezing modes. The diameters of the selected pollen were between 25 and 70 mum. The experiments were carried out at the Mainz vertical wind runnel with freely suspended supercooled droplets at temperatures down to -28 degreesC. The immersion freezing experiments were conducted with drops of radii between 250 and 375 mum formed from distilled water with a defined amount of pollen added. The drops were freely floated in the wind tunnel while being supercooled. For the contact freezing experiments, a short burst of pollen was allowed to collide with freely suspended, supercooled pure water drops of 360-mum radius. The results showed that particle-free water drops in particle-free air in the wind tunnel did not freeze at temperatures above -28 degreesC while water drops containing pollen froze at temperatures as high as -9 degreesC, and water drops colliding with pollen froze at temperatures -5 degreesC and lower. Combined with earlier results about the ice nucleating ability of some bacteria, marine plankton, and leaf litters, the present results confirm the importance of biological aerosol particles as potential ice nuclei at relatively warm temperatures. (C) 2002 Elsevier Science B.V. All rights reserved.