Ionospheric Response to the December 14, 2020 Total Solar Eclipse in South America

Abstract

AbstractThe Southern Andes, in Patagonia, are a well‐known hotspot of orographic gravity waves (oGWs) during winter when atmospheric conditions, such as temperature, wind speed, and wind direction, favor their generation and propagation. In the summer, oGWs above the mesosphere and oGW‐induced ionospheric perturbations are rarely observed because vertical wave propagation conditions are unfavorable. Nevertheless, when atmospheric conditions deviate significantly from those typical of summer, for example, during a solar eclipse (SE), the atmospheric temperature and wind changes can allow oGWs to reach ionospheric heights. Global Navigation Satellite Systems (GNSS)‐based ionospheric total electron content (TEC) studies of the 2017 North American eclipse showed oGW‐compatible observations near the totality zone around the Rocky Mountains, and it was suggested, but not shown, that these were likely oGWs. In this work, we report, model, and interpret GNSS TEC perturbations observed during the December 14, 2020 total SE in South America. TEC data recorded near the Andes during this total SE are in good agreement with predictions by the SAMI3 ionospheric model until shortly after the passage of the umbra. TEC data after totality can best be explained with the interpretation that the observation of oGWs was favored by the passage of the eclipse over the Andes Mountains.