GPS Solutions

, 14:75 | Cite as

Electron density profiles in the equatorial ionosphere observed by the FORMOSAT-3/COSMIC and a digisonde at Jicamarca

  • Jann-Yenq Liu
  • Chien-Chih Lee
  • Jhih-Yung Yang
  • Chao-Yen Chen
  • Bodo W. Reinisch
Original Article


We examine for the first time the ionospheric electron density profiles concurrently observed by the GPS occultation experiment (GOX) onboard the FORMOSAT-3/COSMIC (F3/C) and the ground-based digisonde portable sounder DPS-4 at Jicamarca (12°S, 283°W, 1°N geomagnetic) in 2007. Our results show that the F3/C generally underestimates the F2-peak electron density NmF2 and the F2-peak height hmF2. On the other hand, when the equatorial ionization anomaly (EIA) pronouncedly appears during daytime, the total electron content (TEC) derived from the radio occultation of the GPS signal recorded by the F3/C GOX is significantly enhanced. This results in the NmF2 at Jicamarca being overestimated by the Abel inversion on the enhanced TEC during the afternoon period.


FORMOSAT-3/COSMIC Digisonde NmF2 hmF2 Equatorial ionization anomaly 



This research work has been supported by the projects of National Space Organization to the National Central University, 98-NSPO(B)-IC-FA07-01(L) and to Ching-Yun University, 98-NSPO(B)-IC-FA07-01(R). BWR was supported by Air Force contract FA8718-06-C-0072.


  1. Bilitza D, Reinisch BW (2008) International Reference Ionosphere 2007: improvements and new parameters. Adv Space Res 42. doi:10.1016/j.asr.2007.07.048
  2. Cheng CZ, Kuo YH, Anthes RA, Wu L (2006) Satellite constellation monitors global and space weather. EOS 87:166CrossRefGoogle Scholar
  3. Hajj GA, Romans LJ (1998) Ionospheric electron density profiles obtained with the global positioning system: results from the GPS/MET experiment. Radio Sci 33:175–190CrossRefGoogle Scholar
  4. Lei J et al (2007) Comparison of COSMIC ionospheric measurements with ground-based observations and model predictions: preliminary results. J Geophys Res 112:A07308. doi:10.1029/2006JA012240 CrossRefGoogle Scholar
  5. Lin CH, Liu JY, Fang TW, Chang PY, Tsai HF, Chen CH, Hsiao CC (2007) Motions of the equatorial ionization anomaly crests imaged by FORMOSAT-3/COSMIC. Geophys Res Lett 34:L19101. doi:10.1029/2007GL030741
  6. Lin CH, Liu JY, Hsiao CC, Liu CH, Lin YC, Cheng CZ, Chang PY, Tsai HF, Fang TW, Chen CH, Hsu ML (2009) Global ionospheric structure imaged by FORMOSAT-3/COSMIC: early results. Terr Atmos Ocean Sci 20. doi:10.3319/TAO.2008.01.18.01(F3C)
  7. Reinisch BW (1996) Modern ionosondes. In: Kohl H, Rüster R, Schlegel K (eds) Modern ionospheric science. European Geophysical Society, Katlenburg-Lindau, pp 440–458Google Scholar
  8. Rocken C, Kuo Y-H, Schreiner W, Hunt D, Sokolovskiy S, McCormick C (2000) COSMIC system description. Terr Atmos Ocean Sci 11:21–52Google Scholar
  9. Schreiner WS, Sokolovskiy SV, Rocken C, Hunt DC (1999) Analysis and validation of GPS/MET radio occultation data in the ionosphere. Radio Sci 34:949–966CrossRefGoogle Scholar
  10. Schreiner W, Rocken C, Sokolovskiy S, Syndergaard S, Hunt D (2007) Estimates of the precision of GPS radio occultations from the COSMIC/FORMOSAT-3 mission. Geophys Res Lett 34:L04808. doi:10.1029/2006GL027557 CrossRefGoogle Scholar
  11. Tsai LC, Tsai WH (2004) Improvement of GPS/MET ionospheric profiling and validation using the Chung-Li ionosonde measurements and the IRI model. Terr Atmos Ocean Sci 15:589–607Google Scholar
  12. Tsai LC, Liu CH, Hsiao TY (2009) Profiling of ionospheric electron density based on the FormoSat-3/COSMIC data: results from the intense observation period experiment. Terr Atmos Ocean Sci 20. doi:10.3319/TAO.2007.12.19.01(F3C)
  13. Tsai LC, Tsai WH, Schreiner WS, Berkey FT, Liu JY (2001) Comparisons of GPS/MET retrieved ionospheric electron density and ground based ionosonde data. Earth Planets Space 53:193–205Google Scholar
  14. Zhang ML, Reinisch BW, Shi J-K, Wu S-Z, Wang X (2006) Diurnal and seasonal variation of the ionogram-derived scale height at the F2 peak. Adv Space Res 37:967–971CrossRefGoogle Scholar

Copyright information

© Springer-Verlag 2009

Authors and Affiliations

  • Jann-Yenq Liu
    • 1
    • 2
  • Chien-Chih Lee
    • 3
  • Jhih-Yung Yang
    • 1
  • Chao-Yen Chen
    • 1
  • Bodo W. Reinisch
    • 4
  1. 1.Institute of Space ScienceNational Central UniversityJhongliTaiwan
  2. 2.Center for Space and Remote Sensing ResearchNational Central UniversityJhongliTaiwan
  3. 3.General Education CenterChing-Yun UniversityJhongliTaiwan
  4. 4.Center for Atmospheric ResearchUniversity of MassachusettsLowellUSA

Personalised recommendations