Multiparametric observation of volcanic lightning: Sakurajima Volcano, Japan
Multiparametric observation of volcanic lightning: Sakurajima Volcano, Japan
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DOI：
10.1002/2015gl067445
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发表时间：
2016-05-16
影响因子：
5.2
通讯作者：
Dingwell, D. B.
中科院分区：
文献类型：
--
作者：
Cimarelli, C.;Alatorre-Ibarguengoitia, M. A.;Dingwell, D. B.
利用同步多参数阵列记录了樱岛火山喷发产生的火山闪电。闪电的物理性质与羽流动力学有关，并通过视频观测（高速和正常速度）以及次声和高采样率大地电磁信号揭示了相关的电磁场变化。数据表明，樱岛火山闪电主要发生在火山口边缘上方几百米的烟羽气体冲断区，在那里，湍流火山喷流的超压决定了粒子的通电，在生长的烟羽中产生复杂的电荷结构。当羽流从射流阶段过渡到对流阶段时，电荷的组织可能会在后期实现。与大气探测和最大烟羽高度数据的比较表明，水成物对樱岛闪蒸产生的影响可以忽略不计，可以更谨慎地考虑作为火山烟羽带电的一个额外因素。
We recorded volcanic lightning generated by Vulcanian explosions at Sakurajima Volcano using a synchronized multiparametric array. Physical properties of lightning are related to plume dynamics, and associated electromagnetic field variations are revealed by video observations (high speed and normal speed) together with infrasound and high sampling rate magnetotelluric signals. Data show that volcanic lightning at Sakurajima mainly occurs in the plume gas thrust region at a few hundred meters above the crater rim, where the overpressure of the turbulent volcanic jets determines the electrification of particles generating a complex charge structure in the growing plume. Organization of charges may be achieved at later stages when the plume transitions from the jet phase to the convective phase. Comparison with atmospheric sounding and maximum plume height data show that the effect of hydrometeors on flash generation at Sakurajima is negligible and can be more prudently considered as an additional factor contributing to the electrification of volcanic plumes.