锡林浩特市火山地质公园平台山顶近地面大气电场变化特征

大气电场强度是大气电学的重要参数.大气电场的准确测量对雷暴和地震的监测、预警等具有重要的意义.利用2015年8月27日气球搭载大气电场仪测量近地面大气电场实验得到的电场数据,分析在特殊地形表面近地面500 m高度内大气电场强度随高度的变化特征.结果表明:晴天条件下,火山喷发形成的熔岩平台山顶上空近地面大气电场强度随高度增加呈指数递减,大气电场的数值和变化范围均较大,尤其是近地面100 m高度内,大气电场值达到1 kV·m-1以上.此外,还通过经验公式得出了近火山灰石地表的大气电导率.受空气中重离子的影响,其电导率远小于全球大气电导率的平均值.实验结果丰富了在特殊地形下大气电场的测量结果,揭示了中国内蒙古锡林浩特地区火山山顶近地面大气电场强度随高度的变化特征.

Characteristics of the Near-surface Atmospheric Electric Field over the Top of a Flat Mountain in Xilin Hot Volcano Geopark

The intensity of the atmospheric electric field is an important parameter of atmospheric electricity. Accurate measurements of the atmospheric electric field are important for the monitoring and warning of thunderstorms and earthquakes. In this paper, the electric field data obtained by a balloon experiment of measuring the near-surface atmospheric electric field on 27 August 2015 is used to study the distribution of the atmospheric electric field with height within 500m near the Earth surface. The results show that fair-weather atmospheric electric field value over the top of a flat mountain rises exponentially with height. Both the values and range of the atmospheric electric field are large, especially within the height of 100m, and the value can reach 1kV·m-1 or more. In addition, the empirical formula is used to derive the atmospheric conductivity near the surface of the Earth. Influenced by heavy ions in the air, the conductivity is much smaller than the average of global atmospheric conductivity. The results of this experiment not only enrich the observations of the atmospheric electric field under special terrain condition, but also reveal the distribution of electric field with height in the near-surface atmosphere of an extinct volcano in Xilin Hot, Inner Mongolia Area, China.