A multi-instrumental and modeling analysis of the ionospheric responses to the solar eclipse on 14 December 2020 over the Brazilian region

Abstract

Abstract. This work presents an analysis of the ionospheric responses to the solar eclipse that occurred on 14 December 2020 over the Brazilian sector. This event partially covers the south of Brazil, providing an excellent opportunity to study the modifications in the peculiarities that occur in this sector, as the equatorial ionization anomaly (EIA). Therefore, we used the Digisonde data available in this period for two sites: Campo Grande (CG; 20.47∘ S, 54.60∘ W; dip ∼23∘ S) and Cachoeira Paulista (CXP; 22.70∘ S, 45.01∘ W; dip ∼35∘ S), assessing the E and F regions and Es layer behaviors. Additionally, a numerical model (MIRE, Portuguese acronym for E Region Ionospheric Model) is used to analyze the E layer dynamics modification around these times. The results show the F1 region disappearance and an apparent electronic density reduction in the E region during the solar eclipse. We also analyzed the total electron content (TEC) maps from the Global Navigation Satellite System (GNSS) that indicate a weakness in the EIA. On the other hand, we observe the rise of the Es layer electron density, which is related to the gravity waves strengthened during solar eclipse events. Finally, our results lead to a better understanding of the restructuring mechanisms in the ionosphere at low latitudes during the solar eclipse events, even though they only partially reached the studied regions.

Ionospheric response modeling under eclipse conditions: Evaluation of 14 December 2020, total solar eclipse prediction over the South American sector

“…These data were obtained from the Ionogram-Derived Characteristics of DIDBase (https://giro.uml.edu/didbase/scaled.php). Although Cachoeira Paulista (22.7 °S, 45 °W) had a maximum of 30% of eclipse obscuration, no differences in foF2 were observed during the eclipse obscuration, as previously indicated by Resende et al (2022). However, a reduction can be observed after the time of the eclipse, at approximately 19 UT.…”

“…Measurements of multiple ground-based instruments along the continent (i.e., ionosonde stations, an Incoherent Scatter Radar, and GNSS receiver networks) and satellites (i.e., Swarm-A) are used to evaluate the accuracy of simulation results, providing a testbed scenario to determine the accuracy of the ionospheric prediction model under total eclipse conditions. In addition, the results of this evaluation are compared to the ionospheric response to the 2 July 2019, solar eclipse that occurred in the same geographical area (Bravo et al, 2020;Jonah et al, 2020;Maurya et al, 2020) and previous studies that evaluated the ionospheric response to the 14 December 2020, solar eclipse (e.g., Gómez, 2021;Meza et al, 2021;Shrivastava et al, 2021;de Haro Barbás et al, 2022;Resende et al, 2022).…”

Blanketing Sporadic‐E Layer Occurrences Over Santa Maria, a Transition Station From Low to Middle Latitude in the South American Magnetic Anomaly (SAMA)

“…This behavior was also confirmed during the 21 August 2017, solar eclipse, when fb Es presented rapid responses to changes in solar radiation (Chen et al., 2021). However, gravity wave events during a solar eclipse can also intensify the Es layers in terms of increases in fb Es (Resende et al., 2022) or in terms of Es layers persistence (Pezzopane et al., 2015).…”

The 14 December 2020 Total Solar Eclipse Effects on Geomagnetic Field Variations and Plasma Density Over South America

“…The RD is calculated by: $$$\mathrm{R}\mathrm{D}=\frac{{\mathrm{T}\mathrm{E}\mathrm{C}}_{\mathrm{e}\mathrm{c}\mathrm{l}}-{\mathrm{T}\mathrm{E}\mathrm{C}}_{\mathrm{r}\mathrm{e}\mathrm{f}}}{{\mathrm{T}\mathrm{E}\mathrm{C}}_{\mathrm{r}\mathrm{e}\mathrm{f}}}\times 100\%$$$ where TEC ecl and TEC ref are the vertical TEC, in TEC units (1 TECu = 10 16 electrons/m 2 ), during the eclipse day and the control day (or reference day), respectively. RD is the relative difference between the TEC ecl and the TEC ref (Resende et al., 2022).…”

“…where TEC ecl and TEC ref are the vertical TEC, in TEC units (1 TECu = 10 16 electrons/m 2 ), during the eclipse day and the control day (or reference day), respectively. RD is the relative difference between the TEC ecl and the TEC ref (Resende et al, 2022). (red) and 17 (orange) December 2020, the average of quiet days (blue) with ±1 standard deviation (blue shaded area), and the obscuration (magenta) in the right axis.…”