11 Oct 2022
11 Oct 2022

Ionosonde and GPS Total Electron Content Observations during the 26 December 2019 Annular Solar Eclipse over Indonesia

Jiyo Harjosuwito1, Asnawi Husin1, Varuliantor Dear1, Johan Muhamad1, Agri Faturahman1, Afrizal Bahar2, Erlansyah Erlansyah3, Agung Syetiawan4, and Rezy Pradipta5 Jiyo Harjosuwito et al.
  • 1Research Center for Space, Research Organization for Aeronautics and Space (LAPAN), National Research and Innovation Agency (BRIN), Indonesia
  • 2Agam Atmospheric and Space Observation Office, Research Organization for Aeronautics and Space (LAPAN), National Research and Innovation Agency (BRIN), Indonesia
  • 3Pontianak Atmospheric and Space Observation Office, Research Organization for Aeronautics and Space (LAPAN), National Research and Innovation Agency (BRIN), Indonesia
  • 4Research Center for Geospatial, Research Organization for Earth Sciences and Maritime, National Research and Innovation Agency (BRIN), Indonesia
  • 5Institute for Scientific Research, Boston College, United States

Abstract. We report our investigation of ionospheric effects due to the passage of an annular solar eclipse over Southeast Asia on 26 December 2019, using multiple set of observations. Two ionosondes (one at Kototabang and another at Pontianak) were used to measure dynamical changes in the ionospheric layer during the event. A network of ground-based GPS receiver stations in Indonesia were used to derive the distribution of total electron content (TEC) over the region. In addition, extreme ultraviolet (EUV) images of the Sun from the Atmospheric Imaging Assembly (AIA) instrument on board the Solar Dynamics Observatory (SDO) satellite were also analyzed to determine possible impacts of solar active regions on the changes that occurred in the ionosphere during the eclipse. We found −1.67 MHz and −1.58 MHz reduction (23.2 % and 22.4 % relative reduction) in foF2 during the solar eclipse over Kototabang and Pontianak, respectively. The respective TEC reduction over Kototabang and Pontianak during the eclipse was −4.34 TECU and −5.45 TECU (24.9 % and 27.9 % relative reduction). Overall, there was 34–36 minutes delay from maximum eclipse until minimum foF2 was reached at these two locations. The corresponding time delays for eclipse-related TEC reduction at these two locations were 40 minutes and 16 minutes, respectively. The ionospheric F-layer was found to descend with a speed of 9–19 m/s during the first half of the eclipse period. We also found an apparent rise of the ionospheric F-layer height near the end of the solar eclipse period, equivalent to vertical drift velocity of 44–47 m/s. The GPS TEC data mapping along a set of cross-sectional cut lines indicate that the greatest TEC reduction actually occurred to the north of the solar eclipse path, opposite of the direction from which the lunar shadow fell. As the central path of the solar eclipse was located just to the north of the southern equatorial ionization anomaly (EIA) crest, it is suspected that such a peculiar TEC reduction pattern was caused by plasma flow associated with the equatorial fountain effect. Net perturbations of TEC were also computed and analyzed, which revealed the presence some wavelike fluctuations associated with the solar eclipse event. Some of the observed TEC perturbation patterns that propagated with a velocity matching the lunar shadow may be explained in terms of non-uniform EUV illumination that arose as various active regions on the Sun went obstructed and unobstructed during the eclipse. The remaining wavelike features are likely to be traveling ionospheric disturbances (TIDs) driven by acoustic-gravity waves (AGWs), generated by the passage of the solar eclipse on top of other diurnal factors.

Jiyo Harjosuwito et al.

Status: final response (author comments only)

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse
  • RC1: 'Comment on egusphere-2022-909', Anonymous Referee #1, 10 Nov 2022
  • RC2: 'Comment on egusphere-2022-909', Anonymous Referee #2, 11 Nov 2022

Jiyo Harjosuwito et al.

Data sets

Scaled Ionogram Parameters and Processed GPS TEC Data Jiyo Harjosuwito

Video supplement

Masked Solar Images and 2-D Regional GPS TEC Maps Jiyo Harjowusito

Jiyo Harjosuwito et al.


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Short summary
An annular solar eclipse passed over Southeast Asia on 26 December 2019. The passage of an eclipse can cause observable effects on the Earth's ionosphere. Studying these effects may help us build a better understanding of the Earth's upper atmosphere and the geospace environment. Taking advantage of the growing network of GPS receivers and existing ionosondes in the region, we examined changes in the low-latitude ionosphere over Southeast Asia during this solar eclipse.