Oral Presentation
Ionospheric electron density and irregularity observations using GPS radio occultation data
Presenter: Lung Chih Tsai (GPSARC/CSRSR, NCU, Taiwan, R.O.C.)
The FS3/COSMIC has been proven a successful mission on performing active limb sounding of the ionosphere using the GPS radio occultation (RO) technique. The electron density (Ne) values can be usually retrieved from the calibrated total electron content values using the Abel integral transform. We have developed a compensatory Abel-inversion scheme to improve vertical Ne profiling and also retrieved ionospheric parameters (foF2, hmF2, etc) for further three-dimensional Ne modeling. We also reprocess 1-Hz amplitude data and obtain complete limb-viewing profiles of the undersampling-S4 scintillation index to study global F-layer irregularity morphology. Seven identified areas Central Pacific Area, South American Area, African Area, European Area, Japan Sea Area, Arctic Area and Antarctic Area have been designated to have a much higher percentage of strong limb-viewing L-band scintillations. Meanwhile, ionospheric sporadic-E (Es) activity and global morphology have also been studied using the 50-Hz signal-noise-ratio amplitude and excess phase measurements from the FS3/COSMIC GPS RO observations. More or less 31% of those observations were identified as Es events based on L1-band amplitude standard deviation (SDL1) and peak SDL1 altitude criteria. We also obtained five major zones in which the seasonal and diurnal patterns of Es occurrence are markedly different. Generally, the F-layer scintillation and Es-layer event climatology, namely, its variations with each identified zone, altitude, season, and local time have been documented.
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