Electric field soundings and the charge structure within an isolated thunderstorm

Abstract

A strong electric (E) field sounding system was designed to measure the vertical component of the E-fields, temperature, relative humidity and GPS data along the sounding path. In the summer of 2008, in situ measurements of E-field inside the thunderstorms were conducted in Pingliang, Gansu Provience, with the cooperation of an X-band weather radar. One E-field profile inside a thunderstorm was successfully acquired. The sounding data indicated four charge layers along the sounding trajectory, three inside the thuderstorm and one at its lower boundary. The lower cloud boundary charge layer was negative, acting as a screening layer, and laid between 4.3 to 4.5 km a.s.l. The lower positive charge center (LPCC) existed between 4.5-5.3 km a.s.l. (from 3°C to −2°C); the main negative charge area was present between 5.4-6.6 km a.s.l. (−3°C to −10°C); the upper positive charge layer was between 6.7-7.2 km a.s.l. (−11°C to −14°C). The results support the tripole charge structure inside thunderstorms (above 0°C isotherm altitude), but the LPCC is much larger-than-usual in Chinese inland plateau. thunderstorm, electric field sounding, electric charge structure, Chinese inland plateau, charging mechanism Citation:Zhao Z K, Qie X S, Zhang T L, et al. Electric field soundings and the charge structure within an isolated thunderstorm.

Electrical soundings in the decay stage of a thunderstorm in the Pingliang region

“…The observations showed that three charge regions existed in the cloud and the negative charge region stayed in the middle part of the cloud. An obvious feature of the charge structure was that each charge region located at a lower altitude when compared with those observed in the mature stage (Zhao et al, 2010). On the one hand, the cloud upper boundary was limited to 6.3 km; on the other hand, the predominant airflow in this stage was a downdraft.…”

“…Secondly, the charging process may not have ceased completely and no lightning flash occurred to consume the charge in the cloud. Zhao et al (2010) found that a thunderstorm in the Pingliang region had four charge regions in the mature stage, alternating in polarity, i.e., an upper positive charge region, a middle negative charge, a lower positive charge center and a negative screening charge layer at the bottom. These results support our observation that the charge structure in the mature stage was not substantially different from that in the decay stage before dissipation of the charge region.…”

“…The charge structure retrieved by multi-station synchronous observation of electric field changes indicated that thunderstorms over the Chinese inland plateau regions possess a tripole charge structure in the mature stage Atmospheric Research 164-165 (2015) 188-193 Cui et al, 2009, Zhao et al, 2010. Using a corona probe radiosonde, Zhao et al (2010) found three charge regions located in the region of the cloud colder than 0°C and a negative screen layer existed at the lower boundary. By using a three dimensional lightning mapping system, Li et al (2013) studied an isolated thunderstorm in Qinghai Province and found that the thunderstorm had an inverted dipole charge structure during its developing and mature stages.…”

Numerical Simulation of the Formation of a Large Lower Positive Charge Center in a Tibetan Plateau Thunderstorm

“…Other observations in the same area have also confirmed the tripole structure in thunderstorms and have provided evidence for the existence of an upper positive charge center (UPCC; Zhang et al, ). In Pingliang (about 1,400 m ASL), another area on the northeastern edge of the Tibetan Plateau, a tripole structure with a large LPCC, was also observed through electric sounding measurements of an isolated thunderstorm (Zhao et al, ).…”

A gigantic jet event observed over a thunderstorm in mainland China

“…These lightnings occur in the troposphere and have been extensively studied [1][2][3][4][5][6][7][8][9][10][11]. However, there are another type of lightning discharges which occur above the thunderstorms, with the top altitude even reaching the ionosphere.…”