| 摘要: | 關鍵詞：全球定位╱氣象系統、無線電波遮蔽觀測、電離層電子密度本子計畫目的在福衛三號密集觀測期電離層研究，目標為：（1）利用全球動態式電離層觀測系統網校正福衛三號電離層參數觀測資料；（2）利用於密集觀測期電離層參數量測資料進行相關全球數值分析，用以供應全球電離層實驗模式(The IRI Model)應用；（3）利用密集觀測期電離層參數量測全電子含量資料進行全球三維電離層斷層掃描圖反演。在本計畫中用以校正與驗證福衛三號密集觀測期電離層電子密度資料為全球動態式電離層觀測系統 (包含低緯度的中壢動態式電離層觀測系統，中緯度的熊湖動態式電離層觀測儀與高緯度的EISCAT, BAS, IRF動態式電離層觀測儀) ，確定未來福衛三號電離層電子密度資料的正確性。本計畫更將運用密集觀測期電離層參數量測資料進行相關全球數值分析改良國際電離層參考模式 (the International Reference Ionosphere (IRI) Model) 中F2 層臨界頻率(foF2)，F2 層臨界頻率高度 (hmF2) ，E 層臨界頻率(foE)，與E 層臨界頻率高度 (hmE)全球數值分佈表。 最後本計畫將利用密集觀測期電離層全電子含量資料進行全球三維電離層斷層掃描圖反演，先前FORMOSAT-3/COSMIC參考實驗研究已利用衛星軌道計算軟體STK模擬未來FORMOSAT-3 /COSMIC計畫中GPS與LEO衛星位置，同時進一步利用電離層實驗模式(IRI) 計算無線電波遮蔽觀測中全電子含量，然後運用MART反演技術求得電離層三維電離層斷層掃描圖，並加以驗證與分析比較，相關已開發軟體可直接運用於福衛三號密集觀測期三維電離層斷層掃描分析與科學研究。 Keywords: GPS/MET, radio occultation observation, ionospheric electron density profile This project is proposed to (1) vilify the retrieval of ionosphseic electronic density using the International Dynasonde Network, (2) map the ionospheric parameters (e.g. foF2, hmF2, foE, and hmE), which can be applied to the IRI model, and (3) produce three-dimensional ionospheric tomography based on the FORMOSAT-3/COSMIC Intense Observation Period (IOP) data. The retrieved foF2, hmF2, foE, hmE results within the FORMOSAT-3 IOP can be used to produce numerical maps representing the complex properties on a world-wide scale. In this study we choose as our coordinate functions a particular set of the functions Gk(？f,？c) of which the surface spherical harmonics are linear combinations and are specified of terms involving with three groups of (1) powers in sin ？f for representing the main latitudinal trend without longitudinal variation, (2) first order sectorial harmonics for representing first order longitudinal variation, and (3) second order tesseral order harmonics for second order longitudinal variation. The derived numerical maps can be compared with the original CCIR and URSI maps. Furthermore, in the study of tomographic imaging of the ionosphere, the FORMOSAT-3/COSMIC use low Earth orbiting (LEO) satellites to receive multi-channel GPS carrier phase signals (1.5GHz and 1.2GHz) and measure the line-of-sight total electron contains (TEC). We have implemented the Multiplicative Algebraic Reconstruction Technique (MART) to reconstruct and compare two-dimensional and three-dimensional ionospheric structures from measured TECs through the receptions of the GPS radio occultation signals. We have conducted a series of ionospheric imaging experiments to investigate the latitudinal structure of the equatorial ionization anomaly and have also concluded the profiles retrieved from tomographic reconstruction showing much reasonable electron density results than the original vertical profiles retrieved by the Abel transformation and being in more agreement in peak electron density to nearby ionosonde measurements. 研究期間：9412 ~ 9511 |
