沙尘暴过程中5～7000m高度大气电场及其对颗粒带电量影响

Exploration of the atmospheric electricity at 5-7 000 m height in sandstorm and its effect on the electrification of sands

利用GPS探空仪和大气电势测量设备,在塔克拉玛干沙漠腹地测量了一次沙尘天气过程中大气电势的梯度分布,基于电场变化曲线分析了空中沙尘颗粒电荷极性及其数目浓度的变化规律,给出了一种新的沙尘颗粒起电机制模型,讨论了环境电场强度对其带电量的影响。结果表明:沙尘天气过程中大气电势强度先增加后减小,在某一高度改变方向,但其强度再次呈现先增加后减小的变化规律。随着环境风沙电场强度的增加,颗粒带电量指数增加,当电场强度超过10 kV·m^-1时其对颗粒电荷量的贡献就可能与离子交换机制的贡献相当。研究结果有助于更为准确地认识沙尘天气过程中大气电场分布规律及其对风沙电现象的影响,同时也有助于设计基于风沙电场测量来获得空中颗粒浓度、带电信息的新方法。

Based on the GPS radiosonde and the atmospheric electric field instruments,a field experiment is carried out in the hinterland of the Taklimakan Desert to explore the atmospheric electricity at 5-7000 m height in a sandstorm process.Through the information of atmosphere electric field along the altitude direction,this paper analyzes the polarity of the charge on particles and the variation law of particle concentration at the upper air.In addition,a new electrification model of sand particle is proposed to clarify the effect of environmental electric field on the particle's electrification.The results showed that the atmospheric electric field firstly increases and then decreases,even reverse its direction at a specific altitude,and then present a same changing rule with the former.Furthermore,based on some numerical simulations,the new physical model of the electrification of sand clarified that the environmental electric field obviously enhanced the electrification process of sand.