Ionospheric Effects During the Total Solar Eclipse Over Southeast Asia‐Pacific on 9 March 2016: Part 1. Vertical Movement of Plasma Layer and Reduction in Electron Plasma Density

Abstract

AbstractWe report our investigation of ionospheric effects that occurred during a total solar eclipse over the Southeast Asia‐Pacific region on 9 March 2016. In particular, here we examine rapid uplift of the ionospheric F‐layer during the eclipse, and reductions of ionospheric plasma density in areas around the eclipse totality. This study used data from ionosondes at Biak and Guam, as well as data from a bistatic HF radio link (∼1300 km apart, cutting across the eclipse totality trajectory) between Biak and Manado. Gridded total electron content (TEC) data from the Madrigal Database were also used for a cross‐comparison. The ionosonde measurements indicate an upward vertical drift velocity in the range of 21−40 m/s in the ionospheric F‐region during the eclipse. Over Biak, foF2 decreased from 10 MHz to 6 MHz (a 40% reduction) during the eclipse. Meanwhile, foF2 over Guam during the eclipse was suppressed for a few hours; lower than the 7‐day average normal level by 3 MHz. The Madrigal GPS TEC data corroborate these ionosonde measurements. Finally, data from the Biak‐Manado HF radio link indicate that the D‐region ionosphere had diminished substantially during the eclipse.