Ionospheric Observation Using Equatorial Atmosphere Radar (EAR) Kototabang for the 26 December 2019 Annular Solar Eclipse Research

Abstract

AbstractSolar eclipse passage can cause some change in the ionosphere, which makes it a valuable event to be studied using multi-instruments. On 26 December 2019, an annular solar eclipse passed in the vicinity of Equatorial Atmosphere Radar (EAR) at Kototabang station. We utilize the EAR's capability to detect field-aligned irregularities (FAI) to discover changes in the ionosphere during the eclipse. Other instruments also supported the EAR observation. The results of EAR observations show some appearance of FAI (strong echo power backscatter) at the altitude of ionospheric E layers (90–100 km) during the solar eclipse. Traces of strong sporadic E layers (with spread) were also observed on ionograms from the FMCW ionosonde at the exact location, confirming the EAR observation. The appearance of FAI and these sporadic E layers were likely to be related to the solar eclipse event. The results of several other studies also supported this hypothesis. On the eclipse day, we found that the ordinarily occurring FAI at 150 km altitude disappeared; meanwhile, on 25 and 27 December 2019, the 150 km altitude FAI was observed. We suspect that the absence of FAI at the height of 150 km was related to the solar eclipse phenomena. Another interesting finding is a spread echo backscatter around noon on 25 December 2019, one day before the eclipse.KeywordsEquatorial atmosphere radar (EAR)Field aligned irregularities (FAI)Solar eclipseSpread echoesSporadic E layers