Analyzing Regional and Local Changes in Irradiance during the 2019 Total Solar Eclipse in Chile, Using Field Observations and Analytical Modeling

Abstract

Solar eclipses are astronomic phenomena in which the Earth’s moon transits between theplanet and the Sun, projecting a shadow onto the planet’s surface. As solar power installed capacityincreases, detailed studies of this region-wide phenomenon’s effect in irradiance is of interest; however,the literature mainly reports its effects on localized scales. A measurement campaign spanningover 1400 km was pursued for the 2 July 2019 total solar eclipse in Chile, to register the event andestablish a modeling framework to assess solar eclipse effects in irradiance over wide regionalscales. This work describes the event and presents an estimation framework to decompose atmosphericand eclipse effects on irradiance. An analytical model was applied to study irradiance attenuationthroughout the Chilean mainland territory, using satellite-derived and astronomical data asinputs compared to ground measurements in eight stations. Results showed good agreement betweenmodel and observations, with Mean Bias Errors of ?0.008 to 0.98 W/m2 for Global HorizontalIrradiance and ?0.004 to ?4.664 W/m2 for Direct Normal Irradiance, with Normalized Root MeanSquared Errors of 0.7–5.8% and 1.4–12.2%, respectively. Energy losses due to obscuration correspondedbetween 20–40% for Global Horizontal Irradiance and 25–50% for Direct Normal Irradianceover Chilean territory.