Compositional and Mineralogical Effects on Ice Nucleation Activity of Volcanic Ash
Compositional and Mineralogical Effects on Ice Nucleation Activity of Volcanic Ash
复制标题
火山灰冰核活性的成分和矿物学影响
DOI：
10.3390/atmos9070238
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发表时间：
2018
期刊：
影响因子：
2.9
通讯作者：
T. Woods
中科院分区：
文献类型：
--
作者：
K. Genareau;S. Cloer;K. Primm;M. Tolbert;T. Woods
火山爆发时产生的火山灰可以作为大气中的冰核，由于冰-冰或冰-灰碰撞产生的摩擦充电而导致火山闪电的发生。在这里，不同的灰样品进行了测试，使用沉积模式和浸没模式的冰成核实验。结果表明，散装成分和矿物丰度没有可测量的影响，在测试的温度下，沉积冻结，因为所有的样品都有类似的冰饱和比。在浸没模式下，在−25 °C时，K2 O含量与冰成核点密度之间存在强正相关性，在−35至−30 °C时，MnO与TiO 2含量之间存在强负相关性。在浸没模式下最有效的样品具有最高的表面积、最小的平均晶粒尺寸、最高的K2 O含量和最低的MnO含量。这些结果表明，虽然灰丰度，这创造了更多的可用表面积成核有显着的影响浸没模式冻结，组合物也可能作出贡献。因此，成分演化的岩浆的高爆炸性喷发创造了必要的参数，以促进颗粒表面上的冰成核，这允许由于冰-冰或冰-灰碰撞而产生的摩擦充电，并有助于在这些事件期间在喷发柱和羽流内频繁发生火山闪电。
Volcanic ash produced during explosive eruptions may serve as ice nuclei in the atmosphere, contributing to the occurrence of volcanic lightning due to tribocharging from ice–ice or ice–ash collisions. Here, different ash samples were tested using deposition-mode and immersion-mode ice nucleation experiments. Results show that bulk composition and mineral abundance have no measurable effect on depositional freezing at the temperatures tested, as all samples have similar ice saturation ratios. In the immersion mode, there is a strong positive correlation between K2O content and ice nucleation site density at −25 °C and a strong negative correlation between MnO and TiO2 content at temperatures from −35 to −30 °C. The most efficient sample in the immersion mode has the highest surface area, smallest average grain size, highest K2O content, and lowest MnO content. These results indicate that although ash abundance—which creates more available surface area for nucleation—has a significant effect on immersion-mode freezing, composition may also contribute. Consequently, highly explosive eruptions of compositionally evolved magmas create the necessary parameters to promote ice nucleation on grain surfaces, which permits tribocharging due to ice–ice or ice–ash collisions, and contribute to the frequent occurrence of volcanic lightning within the eruptive column and plume during these events.
影响因子：
5.2
作者：
Van Eaton, Alexa R.;Amigo, Alvaro;Behnke, Sonja A.
通讯作者：
Behnke, Sonja A.
影响因子：
6.3
作者：
Murray, B. J.;Broadley, S. L.;Wills, R. H.
通讯作者：
Wills, R. H.