## 3 Results
### Characterization of the Atmospheric Electrical Activity  
Within the study region, on 10 November 2018, two thunderstorms were observed in the subregion defined between latitudes 43\({}^{\circ}\) S-28\({}^{\circ}\) S and longitudes 70\({}^{\circ}\) W-51\({}^{\circ}\) W (yellow box in Figure 3). The storm cell located in the central region started at 23:00 UTC, and the storm cell located in the southeast started at 16:00 UTC on 9 November 2018, both cells with southeastward motion. Around 04:00 UTC on 10 November 2018, both storms merged into a large system. They reached their dissipation stage at around 16:00 UTC on that day. Their dissipation stage was short-lived, due to the generation of other storms that merged with them. During the selected analysis period, from 00:00 UTC to 08:00 UTC, the storm cells reached cloud tops below \(-70\)\({}^{\circ}\)C, which suggests that the storms achieved their maximum vertical development. This is shown in Figure 3, where the color bar illustrates the range of brightness temperatures (BT). The colder colors correspond to BT values ranging between \(-60\)\({}^{\circ}\)C and \(-40\)\({}^{\circ}\)C, while the warmer colors represent BT from \(-80\)\({}^{\circ}\)C to \(-70\)\({}^{\circ}\)C. The colors ranging from gray to black indicate temperatures between \(-90\)\({}^{\circ}\)C and \(-80\)\({}^{\circ}\)C. Zones of deep convection are delineated by warm colors and colors ranging from gray to black. During the night of 10 November, between 00:00 UTC and 08:00 UTC, a total of 128,939 discharges were recorded, with 40% being \(-\)IC (negative intracloud) and 3% being +CG (positive cloud-to-ground). Figures 4 and 5 depict the detected lightning discharges at a given moment. The graphics classify the discharges based on type and polarity as follows: positive +CG (light blue star) and +IC (green diamond); negative \(-\)CG (blue star) and \(-\)IC (brown diamond). By examining the images, it can be observed that, during these time intervals, the majority of the recorded discharges are associated with \(BT\leq-70\) \"C, indicating their proximity to deep convective zones. Considering the estimated peak current of the discharges, we find that CG-type discharges exhibit maximum peak current values exceeding 200 kA, while IC-type discharges reach values around 30 kA (see Table 1). These peak currents are located over the regions of maximum lightning counts, which are observed in Figure 6. In that figure, the lightning counts are spatially illustrated on a 0.2\({}^{\circ}\) by 0.2\({}^{\circ}\) grid, where the light colors represent the locations with the highest counts. The highest lightning counts are found at the northwest end of the cell located in the southeast region, reaching values above 2290 discharges. Figure 3: GOES-R 16 image, channel 13 (10.3 \(\upmu\)m). Plots are made every two hours from 18:00 UTC on 9 November 2018 to 16:00 UTC on 10 November 2018. The study subregion, defined between latitudes 43\({}^{\circ}\) S-28\({}^{\circ}\) S and longitudes 70\({}^{\circ}\) W-51\({}^{\circ}\) W, is outlined in yellow. Figure 4: Evolution of hourly storms from 00:00 UTC to 03:00 UTC in the study subregion. Diamonds are used to represent IntraCloud (IC) discharges (brown for \(-\)IC and green for +IC), and stars to represent Cloud-to-Ground (CG) discharges (blue for \(-\)CG and light blue for +CG). The color scale represents the brightness temperature corresponding to band 13 of the ABI sensor, GOES-R 16. Figure 5: Same as Figure 4 for storms from 04:00 UTC to 07:00 UTC. To analyze the temporal variation in discharges, we examined the distribution of relative frequencies of discharges per hour (left panel of Figure 7) and per time period (right panel of Figure 7). Dividing the discharges into time periods allowed us to investigate their relationship with the ionosphere, which is analyzed in the next section. Looking at the graph on the left, we could recognize an increase in atmospheric electrical activity (AEA) during the early hours.