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姓名 邱柏勳(Po-Hsun Chiu) 查詢紙本館藏 畢業系所 太空科學與工程研究所 論文名稱 利用流星雷達進行中高層大氣風場的觀測與研究 相關論文 檔案 [Endnote RIS 格式]
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至系統瀏覽論文 (2025-8-1以後開放)
摘要(中) 國立中央大學已於民國112年3月正式建置完成一套雙態流星雷達系統，由位於中壢電離層觀測站的發射系統，與位於新屋氣象站的接收系統所組成。發射頻率為39.9MHz，雷達波為圓形極化波，發射與接收天線系統由3單元交叉八木天線所構成，其中發射天線為單根交叉八木天線，接收天線為由5根交叉八木天線排列成十字型的天線陣列所組成。
本研究分析112年3月10至25日流星雷達所觀測的低密度流星尾回波，利用所推導的雷達干涉法與不同天線對的流星尾回波相位差，根據所發展的流星回波辨識演算法，成功開發並利用「反推比較法」，可解決回波相位混淆問題，計算出流星尾回波的正確天頂角、方位角以及高度，進而定位出流星尾的空間位置。由回波都普勒頻移，透過矩陣計算以及動窗法(Sliding Window)的濾波平滑，得到高度80至110公里範圍內的中高層大氣水平風場，包含東西向與南北向風場，並與水平風場模式(HWM, Horizontal Wind Model)以及廠商提供於雷達系統內部的軟體計算出的參數比較，三者之間的風場變化趨勢有一致性，並可觀察出明顯的全日潮(Diurnal Tide)現象，利用不同高度層間的風速大小隨時間的移動變化，進而計算出重力波造成的相速度大小，並符合理論值。摘要(英) In March 2023, a new set of bistatic meteor radar system was constructed by National Central University. This radar system consists of a transmitter system located at Chung-Li Ionospheric Observatory and a receiving system situated at Xinwu Meteorological Station with a horizontal separation of about 20 km. The operating frequency of the radar wave is 39.9MHz with circular polarization. The transmission antenna is a cross 3-element Yagi antenna, and the receiving antenna consists of 5 cross 3-element Yagi antennas arranged in a cross array. In this study, the underdense meteor trail echoes observed by this meteor radar for the period 10-25 March 2023 were analyzed. The interferometry equation and algorithm of sifting and identifying underdense meteor trails are derived and developed, respectively. On the basis of the phase differences between antenna pairs and the configuration of the receiving antenna array, the azimuth angle, zenith angle and true height can be estimated. With these information incorporating Doppler frequency of the meteor trail echoes, the wind velocity can be estimated from the matrix operation. The smoothed horizontal wind velocities in a height range of 80 to 120 km can be obtained by using a sliding window to process the estimated raw wind velocities. It shows that the semidiurnal tides essentially dominate the horizontal wind variations over time through out the height range 80-120 km. Our results are very consistent with the Horizontal Wind Model (HWM) not only in phase, but also in magnitude. However, detailed examination shows that our results of horizontal wind velocities are about a factor of 2 smaller than those retrieved from the algorithm developed by the system manufacturer, irrespective of our results are in general comparable to the HWM model predictions. This discrepancy in the horizontal wind velocities should be thoroughly investigated and clarified in near further. 關鍵字(中) ★ 流星
★ 雷達關鍵字(英) 論文目次 目錄
摘要 i
Abstract ii
致謝 iii
目錄 v
圖表目錄 vii
第一章 前言 1
1.1 研究動機 1
1.2 流星現象 1
第二章 流星雷達系統簡介與流星尾回波理論 2
2.1 SKiYMET - GS流星雷達系統簡介 2
2.2 低密度流星尾散射方程式 11
2.3 流星尾回波基本處理與分類 18
第三章 雷達干涉法理論 20
3.1 相關函數分析 20
3.1.1 自相關函數 20
3.1.2 互相關函數 21
3.2 雷達干涉法方程式推導 22
第四章 流星雷達回波分析與處理 29
4.1 系統相位校正 29
4.2 相位混淆處理 30
4.2.1 幾何邏輯法 31
4.2.2 反推比較法 32
4.3 定位模擬 33
4.4 雷達參數設定與回波資料介紹 34
4.5 流星尾自動篩選機制 35
4.6 流星尾回波統計結果 40
4.7 流星尾回波定位結果 44
4.8 流星尾回波與系統比較 55
第五章 流星尾風場分析 65
5.1 水平風場計算 65
5.2 流星尾回波演算法風場與HWM模式和系統軟體比較 74
5.2.1 水平風速比較 74
5.2.2 演算法、系統軟體與HWM模式比較 78
5.2.3 風切計算與比較 83
第六章 結論與未來展望 90
6.1 結論 90
6.2 未來展望 91
參考文獻 92參考文獻 (1) Woodman, R. F., & Guillen, A. (1974). Radar observations of winds and turbulence in the stratosphere and mesosphere. Journal of Atmospheric Sciences, 31(2), 493-505.
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