The ionospheric responses to the total solar eclipse on 2 July 2019 over low latitudes in southern South America are presented. Ionosonde observations were used within the totality path at La Serena (LS: 29.9°S, 71.3°W) and at Tucumán (TU: 26.9°S, 65.4°W) and Jicamarca (JI: 12.0°S, 76.8°W), with 85% and 52% obscuration, respectively. Total electron content (TEC) estimations over the South American continent were analyzed. The ionospheric impact of the eclipse was simulated using the Sheffield University Plasmasphere-Ionosphere Model (SUPIM) at the Instituto Nacional de Pesquisas Espaciais (INPE). The significant variability of the diurnal variations of the various ionospheric characteristics over equatorial and low latitudes on geomagnetically quiet days makes it difficult to unambiguously determine the ionospheric responses to the eclipse. Nonetheless, some specific issues can be derived, mainly using simulation results. The E and F1 layer critical frequencies and densities below 200 km are found to consistently depend on decreasing solar radiation. However, the F1 layer stratification observed at both TU and LS cannot be related to the eclipse or other processes. The F2 layer does not follow the changes in direct solar radiation during the eclipse. The SUPIM-INPE-modeled F region critical frequency and TEC are overestimated before the eclipse at LS and particularly at TU. However, these overestimations are within the observed large day-today variability. When an artificial prereversal enhancement is added, the simulations during the eclipse better reproduce the observations at JI, are qualitatively better for LS, and are out of phase for TU. The simulations are consistent with conjugate location effects.

No abstract

No abstract

The first report on the changes in meteorological parameters during the total solar eclipse of July 2, 2019, in La Serena (Chile), is presented. The event could be observed from morning time on the east of New Zealand, in the South Pacific Ocean, to sunset time in Chile. Several meteorological properties such as global radiation Rg, net radiation Rn, reflected radiation Rr (in Wm–2/min), air temperature (TA in °C), relative humidity (RH in %), wind speed amplitude (WS in ms–1), and wind speed direction (WD in degrees), were recorded with La Serena weather station SER (29.827°S, 71.261°W, 28 masl) at 1‑minute time resolution. Importantly, SER was located at 40 km from the axis of the umbra that covered 201 km of width, where it reached 100% darkness at a magnitude of 1.009 during a clear-sky day. Under these auspicious conditions, we observed a rate of changes in the drop of the radiation components of 3.1, 2.4, and 0.5 (Wm–2/min) for Rg, Rn, and Rr, respectively, with a 100% reduction in the components of surface solar radiation (0 Wm–2) during totality. In addition, all components showed a ~34% energy loss during the eclipse in comparison with the day before the event. Also, the rate of changes of –3.3 °C in TA, +11% in RH, –1.11 ms–1 in WS, and 180° to 340° for WD in total synchrony with the passing of the moon in front of the sun, reaching respective peaks at ~5 min lag with respect to totality. Thus, our results show a progressive change in all meteorological parameters in total synchrony with the eclipse’s phases caused by the passing of the moon in front of the sun.