GPS radio occultation measurements on ionospheric electron density from low Earth orbit
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Since the proof-of-concept GPS/Meteorology (GPS/MET) experiment successfully demonstrated active limb sounding of the Earth’s neutral atmosphere and ionosphere via GPS radio occultation (RO) from low Earth orbit, the developments of electron density (ne) retrieval techniques and powerful processing systems have made a significant progress in recent years. In this study, the researches of ne profiling from space-based GPS RO observations are briefly reviewed. Applying to the Formosat-3/Constellation Observing System for Meteorology, Ionosphere and Climate (FS3/COSMIC) data, we also present a compensatory Abel inversion technique including the effects of large-scale horizontal gradients and/or inhomogeneous ionospheric ne obtained from an improved near real-time phenomenological model of the TaiWan Ionospheric Model. The results were evaluated by the ionosonde foF2 and foE data and showed improvements of rms foF2 difference from 29.2 to 16.5% in relative percentage and rms foE difference from 54.2 to 32.7% over the standard Abel inversion.
KeywordsIonospheric electron density Radio occultation Abel inversion
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- Davis HF (1989) Fourier series and orthogonal functions. Dover, New YorkGoogle Scholar
- Hajj GA, Lee LC, Pi X, Romans LJ, Schreiner WS, Straus PR, Wang C (2000) COSMIC GPS ionospheric sensing and space weather. Terr Atmos Ocean Sci 11(1): 235–272Google Scholar
- Piggott WR, Rawer K (1978) U.R.S.I. Handbook of ionogram interpretation and reduction, 2nd edn. World Data Center A for Solar-Terrestrial Physics, Report UAG-23AGoogle Scholar
- Straus PR (1999) Correcting GPS occultation measurements for ionospheric horizontal gradients. In: Proceedings of iono-spheric effects symposium, Alexandria, VA, JuneGoogle Scholar
- Tricomi FG (1985) Integral equations. Dover, MineolaGoogle Scholar
- Tsai L-C, Tsai WH (2004) Improvement of GPS/MET ionospheric profiling and validation with Chung-Li ionosonde measurements and the IRI. Terr Atmos Ocean Sci 15(4): 589–607Google Scholar
- Tsai L-C, Liu CH, Hsiao TY, Huang JY (2009b) A near real-time phenomenological model of ionospheric electron density based on GPS radio occultation data. Radio Sci 44. doi:10.1029/2009RS004154