電離層散塊E層不規則體結構與特性之研究; Interferometry Investigations of Dynamic Behavior in Es Region Using Chung-Li VHF Radar

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Title:	電離層散塊E層不規則體結構與特性之研究;Interferometry Investigations of Dynamic Behavior in Es Region Using Chung-Li VHF Radar
Authors:	楊國峰;Kuo-Feng Yang
Contributors:	太空科學研究所
Keywords:	不規則體;散塊E層;中壢特高頻雷達;irregularities;sporadic E;Chung-Li VHF Radar
Date:	2008-07-11
Issue Date:	2009-09-22 09:46:54 (UTC+8)
Publisher:	國立中央大學圖書館
Abstract:	本文利用位於中緯度地區之中壢特高頻雷達進行電離層散塊E層三公尺場列不規則體觀測，並且經由干涉技術重建場列不規則體電漿三維結構，一般來說可簡單分類為層狀、團狀及鬆散結構，由於各種不同結構之場列不規則體特徵相異因此應分別討論與研究，針對層狀結構不規則體，本文發展出反演層狀結構三維空間姿態之技術並討論其形成機制，對於團狀結構不規則體則是利用波束加寬效應理論研究其凍結效應特性(Chu et al., 2007)，並藉此推算出電漿結構整體真實速度。由於舊有雷達系統已不堪使用，中壢特高頻雷達於2008年1月完成52MHz雷達系統更新，電離層觀測天線陣列也一併更新為倒品字型陣列，此外本文中利用2008年2月5日所得之觀測資料對中緯度電離層F層進行分析與討論。為瞭解電離層電子濃度的分佈及其特性本文利用FORMOSAT-3/COSMIC衛星資料進行分析，為了從原始數據選擇可信度較高的剖面資料，適當的資料品質控管、篩選方法建立是必要的，因此本文提出針對COSMIC衛星電離層E層電子濃度剖面資料篩選方法，並與查普曼理論、電離層觀測儀互相驗證，由於F層資料特性的不同另外定義篩選門檻並與國際電離層參考模式(IRI)比較。 Abstract The Chung-Li VHF Radar located in mid-latitude area was employed to observe 3-m scale sporadic E field aligned irregularities in this research, besides, 3 dimensional spatial structure of field aligned irregularities was reconstructed by using interferometry technique. In generally, field aligned irregularities could be classified into 3 spatial structures which are layer structure, blob structure and loose structure. Discussion and research were made separately according to different structure. For layer structure irregularities, a retrieved technique to reconstruct its spatial structure has been developed and the mechanism is also discussed in this thesis. Theory of Beam broadening effect is implemented here to study the frozen-in effect of blob structure irregularities (Chu et al., 2007); moreover, the true velocity of entire blob structure is calculated according to beam broadening theory. Due to the damage of former Radar system, a renew action of Chung-Li 52MHz Radar system was completed in January, 2008. The former antenna array employed for ionospheric observation has been rearranged to become an isosceles triangle. A new expected echoing region of latest Radar system was analyzed and modeled by using IGRF model according to the characteristic of field aligned irregularities; in the mean time, the accuracy of new expected echoing region was also checked by elementary observation. To understand the distribution and property of ionospheric electron density, data of satellite FORMOSAT-3/COSMIC was analyzed in this research. For getting higher trustworthy profile data, it is necessary to establish a suitable method for data quality control; hence, a conditional selection method was brought up to control the quality of the profile data of ionospheric E region collected by COSMIC, this results were also verified by chapman theory and ionosonde. Another condition for the selection of F region data was defined due to its different characteristic and its results were compared to IRI model.
Appears in Collections:	[Graduate Institute of Space Science] Department of Earth Sciences

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