運用COSMIC全球分佈的RO觀測的電漿濃度（Ne）垂直剖面資料所製作出的臺灣自主電離層數值模式(TaiWan Ionospheric Model,TWIM)，此電離層模式為純粹以實際觀測資料所建構的經驗模式，可提供2007年至今全球電離層各層的峰值濃度（fc）、峰值高度（hm）與其標尺高（H）。利用此模式我們分別對於赤道異常現象各特徵與變化進行研究與討論。其中包含了驗證赤道異常現象在日、季、年等不同時間尺度上的變化與其特徵，並討論東向電場與赤道異常現象的關係、電離層冬季異常現象、太陽活動力對電離層濃度的影響和赤道異常現象的發展與噴泉效應關係。

The TaiWan Ionospheric Model (TWIM) is a numerical and phenomenological model of global ionospheric electron density (Ne) and is constructed from monthly-weighted and hourly vertical Ne profiles retrieved from FormoSat3/COSMIC GPS radio occultation measurements. TWIM can also provide global F2-layer critical frequency (foF2), peak density height (hmF2), and scale height (HF2) maps to study features of equatorial ionospheric anomaly (EIA). The modeling study investigates the diurnal and seasonal variations of EIA and specifically attempts to account for the latitudinal and longitudinal structures. This paper also shows that the neutral winds could cause the north-south asymmetries and longitudinal variation. Furthermore, the phenomena of EIA were also varied with the solar activity. The foF2 values in 2007 are higher than those in 2008 generally, with the exception in March. This variation and exception match to the different of the observational sunspot number between 2007 and 2008.

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