Observations of Electric Fields Sounding in the Mature Stage of a Thunderstorm

Abstract

In the summer of 2021, observations of balloon-borne electric field within thunderstorms were conducted in Nanchang City, Jiangxi Province, China. On 24 August, two electric field profiles were obtained during the mature stage of a local thunderstorm in Nanchang City, Jiangxi Province, China. The initial sounding (S1) and subsequent sounding (S2) were initiated with a 6 min interval. However, S1 entered the weak echo region from the leading edge of the thunderstorm and entered the 30 dBZ region at an altitude of 6 km, while the second sounding (S2) entered from the cloud base and entered the strong echo region at approximately 0°C. At altitudes more than 6 km, the observations were synchronized (with a horizontal distance of 3–4 km). The results showed that two sounding balloons traversed a total of 8 and 11 charge regions for S1 and S2, respectively, and the predominant charge regions conformed to the tripole charge structure. The synchronized observations above 6 km indicated that the distribution of charge regions within the thunderstorm indeed exhibits horizontal inhomogeneity. In addition, an anomalous negative charge region was identified in the upper portion of the thunderstorm, with a depth ranging from 2.3 to 2.7 km, which is larger than the normal negative screening layer. It is notable that a pair of charges with negative upper and positive lower charges is observed at 8.5 and 10 km, which is difficult to explain reasonably using non-inductive charging mechanisms. This indicates the complexity of the formation of charge region within clouds.