基于双金属球三维电场探空仪的一次雷暴云内电荷结构观测研究

本文自主研制性能稳定的双金属球三维电场探空仪,并结合气象探空仪等构建了雷暴电场-气象综合探空系统,实现了雷暴云内三维电场及温度、湿度的同步测量.2019年夏季对华北平原地区雷暴开展穿云观测,并结合地面大气电场、雷达回波、变分多普勒雷达分析系统(VDRAS)反演的动力场等资料进行综合研究,首次给出该地区雷暴云内的电场和电荷结构分布特征.对2019年8月7日发生的一次中尺度对流系统电场探空发现,在雷暴减弱阶段,其弱回波区内存在5个极性交替的电荷区:4.4~5.6 km之间的上部正电荷区(0℃附近)、3.6~4.4 km之间的中部负电荷区和1.0~3.6 km之间的下部正电荷区,此外在1 km下方有一个负极性电荷区,雷暴云顶附近5.7~6.9 km之间为一个弱负极性屏蔽电荷区.其中,中部负电荷区和下部正电荷区由多个不同强度、不同厚度的电荷层构成.此外,电场探空系统在中部负电荷区高度范围内经历的上升—下沉—再次上升的往返探空数据表明,雷暴云内动力环境复杂,电荷结构分布相似但又有所差异,反映了实际雷暴云内电荷分布的时空不均匀性和复杂性.

The charge structure in a thunderstorm based on three-dimensional electric field sonde

A double-metal-sphere three-dimensional electric field sonde was developed successfully,and the thunderstorm electric-meteorological integrated sounding system was constructed in combination with weather radiosonde to measure the comprehensive sounding data of electric field,temperature and relative humidity.In summer of 2019,the field experiment was carried out in the North China Plain.The vertical electric filed profile and the corresponding charge structure inside the thunderstorm in this region are presented for the first time,through analyzing the sounding data,and synchronous surface electric field,radar echo and the three-dimensional wind field given by Variational Doppler Radar Analysis System(VDRAS).The sounding system was released during the dissipation stage of a mesoscale convective system(MCS)on August 7,2019 and passed through the weak echo region of the thunderstorm.The sounding results show that there were five charge regions in the thunderstorm and the charge polarity altered in the vertical direction.The upper positive charge region was at 4.4~5.6 km(near 0℃),and the complex middle negative charge region was at 3.6~4.4 km.The height of lower positive charge region was 1.0~3.6 km.Besides,there was a negative charge region below 1 km,and a weak negative shielding charge region was near the top of the thunderstorm.Both middle negative charge region and lower positive charge region were composed of several charge layers with different thicknesses and charge densities.Furthermore,the electric field sounding system experienced the stages of rising,falling and rising again during 3.6~4.4 km,which were in the range of the middle negative region.The sounding data indicates that the dynamic field inside the cloud was complicated,and the detailed charge structures of the three stages in the negative charge region were similar but different,which reflected the real charge structure inside the thunderstorm was very complicated and inhomogeneous spatio-temporally.