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

Abstract

In this work, we evaluate the SUPIM-INPE model prediction of the 14 December 2020, total solar eclipse over the South American continent. We compare the predictions with data from multiple instruments for monitoring the ionosphere and with different obscuration percentages (i.e., Jicamarca, 12.0°S, 76.8°W, 17%; Tucumán 26.9°S, 65.4° W, 49%; Chillán 36.6°S, 72.0°W; and Bahía Blanca, 38.7°S, 62.3°W, reach 95% obscuration) due to the eclipse. The analysis is done under total eclipse conditions and non-total eclipse conditions. Results obtained suggest that the model was able to reproduce with high accuracy both the daily variation and the eclipse impacts of E and F1 layers in the majority of the stations evaluated (except in Jicamarca station). The comparison at the F2 layer indicates small differences (<7.8%) between the predictions and observations at all stations during the eclipse periods. Additionally, statistical metrics reinforce the conclusion of a good performance of the model. Predicted and calibrated Total Electron Content (TEC, using 3 different techniques) are also compared. Results show that, although none of the selected TEC calibration methods have a good agreement with the SUPIM-INPE prediction, they exhibit similar trends in most of the cases. We also analyze data from the Jicamarca Incoherent Scatter Radar (ISR), and Swarm-A and GOLD missions. The electron temperature changes observed in ISR and Swarm-A are underestimated by the prediction. Also, important changes in the O/N2 ratio due to the eclipse, have been observed with GOLD mission data. Thus, future versions of the SUPIM-INPE model for eclipse conditions should consider effects on thermospheric winds and changes in composition, specifically in the O/N2 ratio.

IonosphericTotal Electron Content Changes during the 15 February 2018 and 30 April 2022 Solar Eclipses over South America and Antarctica

“…The minima with respect to the background values of DVTEC, DN e , and DT e were −52%, −54% to −21%, and <−20%, respectively, under the penumbra of the eclipses of 2018 and 2022. Our DVTEC and DN e results are consistent with the data provided in prior publications [34,48,75]. Also, our T e decrease values are consistent with the findings of earlier studies.…”

“…PSE2018 and PSE2022 had similar ionospheric behaviors under the lunar shadow with clear TEC decreases (<−40%) that moved from Antarctica to South America (see Figures 4 and 5). Despite the fact that the maximum obscuration in both eclipses is around 60% at 350 km altitude, the DVTEC values we obtained were consistent with the values presented for the total solar eclipses over South America [6,10,11,13,27,31,43,45,46,48] and Antarctica [49]. Also, τ values were between 1 and 45 min, and the ionospheric effects caused by PSE2018 and PSE2022 persisted after 24 UT because the concentration of electrons does not return to normal levels (see Figure 6 and Table 1).…”

“…These TEC changes spread over South America as time passed. Our percentage of TEC depletion matches what [27,48] showed in the southern EIA crest for TSE2020 over South America and the EIA depletion summary for different eclipses (DVTEC ∼−50 to −20%) by [27]. At least the eclipses of 2018 and 2020 happened in the summer hemisphere.…”

“…They reported the evident decrease in equatorial electrojet (<−29%) during the solar eclipse, in comparison with non-eclipse. Recently, Bravo et al [48] used data from multiple instruments (ionosondes, an Incoherent Scatter Radar, GNSS stations, and GOLD and Swarm-A missions) to evaluate the ionospheric prediction for a solar eclipse over South America conducted by [44]. Bravo et al [48] also compared the predictions with three different GNSS-TEC estimation methods.…”

“…Recently, Bravo et al [48] used data from multiple instruments (ionosondes, an Incoherent Scatter Radar, GNSS stations, and GOLD and Swarm-A missions) to evaluate the ionospheric prediction for a solar eclipse over South America conducted by [44]. Bravo et al [48] also compared the predictions with three different GNSS-TEC estimation methods. Furthermore, they contrasted their evaluation's findings with earlier studies of the ionospheric behavior of TSE2019 and TSE2020.…”