Changes in meteorological parameters during the total solar eclipse of 2 July 2019 in La Serena, Chile

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.