Charge Structure of Two Tropical Thunderstorms in Colombia

Abstract

Charge structure derived from lightning leader development of tropical thunderstorms comprising equatorial latitudes of less than ±10° has not been investigated yet. In this work, using a lightning mapping array installed in northern Colombia, the charge structure, lightning leader initiations, and the cloud‐to‐ground strokes rates of two thunderstorms have been analyzed. Additionally, radar information is also included. The identification of the charge regions has been obtained by analyzing the propagation of lightning leader developments. Flashes initiate between 4‐ and 15‐km altitude. High initiation rates are different in the two storms. In one case the high rates are found between 8 and 13 km. In the other case, the initiation heights are found between 10 and 15 km. The storms show typical tripolar charge structure where the upper positive charge is present at 10 to ~15 km, the midlevel negative charge is found between 6 and 9 km, and the lower positive charge between 4 and 6 km altitude. Intracloud lightning flashes with inverted polarity have been identified for short period. In other periods, screening layer flashes have been detected at 14–15 km. The overall results show that the charge structures in the two Colombian storms are similar to the structures reported in North Central Florida, but with the significant difference that the flash initiation altitudes are 2 km higher in Colombia. The vertical configuration of the charge regions and the leader development of these thunderstorms may help explain the occurrence of terrestrial gamma‐ray flashes in tropical thunderstorms.

Gigantic jet discharges evolve stepwise through the middle atmosphere

“…The highest current moment during the TJ is 37.5 kA km. Assuming most of the current to flow between the negative cloud charge at ~8 km 39 and TJ top at 50–55 km at that time, this stage produced about 850 A. The current density at 30 km altitude where the channel diameter was 550 m is 3.5 × 10 −3 A m −2 .…”

On the TGF/Lightning Ratio Asymmetry

“…In order to understand the implications of an elevated negative charge region, we have computed a simple model of the thundercloud electric field (Riousset et al, ; Krehbiel et al, ). We have assumed a thundercloud electric charge structure based on Riousset et al (), with four charge regions that are considered to be uniformly charged disks but taking altitudes of the charge regions from Lightning Mapping Array measurements in Colombia from López et al (). The dimensions and charge of the disks are specified in Table and is represented in Figure 12a.…”

A Simultaneous Observation of Lightning by ASIM, Colombia‐Lightning Mapping Array, GLM, and ISS‐LIS

“…As ground support for the ASIM mission, the group at the Polytechnic University of Catalonia (UPC) installed one LMA in the Ebro river delta in North‐Eastern Spain and another in Colombia (López et al., 2019; van der Velde & Montanyà, 2013). At the time of the event, the Colombia‐LMA was composed of six stations close to the city of Barrancabermeja (∼7°N, 73.85°W) in Colombia.…”

“…As ground support for the ASIM mission, the group at the Polytechnic University of Catalonia (UPC) installed one LMA in the Ebro river delta in North-Eastern Spain and another in Colombia (López et al, 2019;van der Velde & Montanyà, 2013 close to the city of Barrancabermeja (∼7°N, 73.85°W) in Colombia. The LMA system detects sources of radio emissions in the very high frequency range (VHF, 30-300 MHz) that originate from the breakdown processes related to the propagation of lightning leaders.…”