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    Please use this identifier to cite or link to this item: http://ir.lib.ncu.edu.tw/handle/987654321/71403


    Title: 台灣地區電離層F層公尺級不規則體之研究
    Authors: 林飛帆;Lin,Fei-Fan
    Contributors: 太空科學研究所
    Keywords: 電離層;F層不規則體;雷達;暉光影像;電離層探測儀;閃爍訊號;ionosphere;F region irregularities;radar;airglow images;ionosonde;S4 index
    Date: 2016-09-29
    Issue Date: 2016-10-13 12:56:53 (UTC+8)
    Publisher: 國立中央大學
    Abstract: 電離層不規則體過去曾由不同儀器進行研究,本文以特高頻雷達、中壢崙坪電離層探測儀、嶼那國島暉光影像、福衛三號COSMIC 衛星,透過不同儀器分析不同尺度之電離層不規則體相互關係,其有利於研究台灣上空F層電漿不規則體特性。同步定位雷達量測之電離層三公尺場列不規則體、暉光上之中尺度電離層行進擾動(MSTIDs)空間位置,三公尺場列不規則體出現在暉光影像耗損區西側邊界,暉光偵測之不同尺度之不規則體以幾乎一致速度30 m/s向東飄移,小尺度不規則體凍結在大尺度不規則體當中向東飄移。且擾動能量傳遞與雷達回波頻譜寬有緊密關係,電子濃度越高區域回波越大。以特高頻雷達觀測台灣北東南上空 (桃園、台東、屏東) F層場列不規則體具以下特徵:不規則體成團狀結構,頻譜寬平均值在30 m/s、平均都普勒速在40 m/s 靠近或遠離雷達站。將特高頻雷達回波訊號與電離圖訊號比較,得到幾項關聯性:在電離層不規則體產生初期,電離層探測儀接收到最大頻率與特高頻回波頻譜寬隨時間一致增加;電離圖散狀F層虛高變化與雷達回波高度有一致相同變化;當雷達回波頻譜寬變小、電離層擾動較微弱時,電離圖上出現反射訊號;當電離層不規則體產生時,電離圖最大頻率隨之先增加後降低。相關台灣上空公尺級電離層不規則體機制於本文中分析與探討。;Ionosphere irregularities have been studied by using ionosondes, VHF radars, airglow images and satelites for several years. In the article, F region plasama irregularities are observed with the VHF radars, the Chung-Li Lunping ionosonde, the Yonaguni airglow image, and the Formosat-3 (COSMIC) satellite. By using the different instruments, the relation of the plasma distubulences detected can be studied at the different scales. The coordinated observation of the F region irregularities associated with the medium scale travelling ionospheric disturbances (MSTIDs) shows that the radar echoes are located at the west edge of the depletion zones of the 630 nm airglow image. The bulk echo structures of the 3-m field aligned irregularities (FAIs) drifted eastward at a mean trace velocity of about 30 m/s that is in general agreement with the zonal trace velocity of the MSTIDs shown in the 630 nm airglow images. These results suggest that the observed F region 3-m FAIs for the present case can be regarded as the targets that are frozen in the local region of the MSTIDs. In addition, the radar-observed 3-m FAI echo intensity and spectral width bear high correlations to the percentage variations of the 630 nm emission intensity. By using the VHF radars in Taoyuan, Taitung and Pingtung, three-meter field-aligned irregularities (FAIs) occurred in nighttime F region over Taiwan. Interferometry measurements show that the plasma structures of the observed 3-m FAIs occurred in a height range of 250-350 km are in a in a clumpy shape. The mean spectral width of the radar echoes is about 30 m/s and the Doppler velocity of the radar echoes is about 40 m/s toward (away from) the radar station. Comparing the VHF radar and the ionosonde ehoes, the studies show that in the beginning of the plasma disturbulences, the maximum frequency on the ionogram increases with the spectral width of the VHF radar echoes. The height of the spread F is associated with height of the 3-m FAIs. The reflection signals are seen on ionograms when spectral widths of the radar echoes are small. The plausible causes of these results are analyzed and investigated in this article.
    Appears in Collections:[太空科學研究所 ] 博碩士論文

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