特高頻雷達閃電回波訊號特性分析

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Please use this identifier to cite or link to this item: http://ir.lib.ncu.edu.tw/handle/987654321/76721

Title:	特高頻雷達閃電回波訊號特性分析
Authors:	江健瑋;Chiang, Chieng-Wei
Contributors:	太空科學研究所
Keywords:	閃電分佈與風場關聯;閃電與氣象雷達之關聯;閃電;雷達干涉法
Date:	2018-07-23
Issue Date:	2018-08-31 11:34:25 (UTC+8)
Publisher:	國立中央大學
Abstract:	本研究使用了中壢52MHz特高頻雷達站的干涉天線陣列，此陣列建立與民國101年，由5座八木天線排列而成的非對稱十字形天線陣列，提供干涉定位所需之5路接收信號；干涉定位必須利用目標物至不同天線間因傳播造成的路程差，進一步的推估出目標物在空間中的位置，本研究使用此干涉天線陣列觀測閃電，最後利用干涉方程式可將閃電在空間中的三維分布完整呈現。可以知道閃電幾乎都是發生在下雨時，本研究比對了中壢特高頻雷達站與中大氣象雷達的資料，發現不同時段閃電發生的頻率與氣象雷達訊號強度有所關聯，進一步的利用統計方法比對兩者之關聯性。比對中央氣象局所提供之氣象雷達回波圖與中壢VHF雷達所觀測之閃電事件分布，發現了閃電的位置會因為雷雨胞之飄移而移動，利用中壢VHF雷達與中大氣象雷達觀測閃電發生時的降水環境做分析，發現三個系統的飄移趨勢相似，進而利用多都卜勒雷達風場合成方法(WISSDOM)所得到之風場與閃電移動速度作比對後，兩者結果相差不遠。 ;In this thesis, used the interferometry antenna array built at Chung-Li 52MHz VHF radar station, this array built in 2012,and the whole antenna array is asymmetrical cross array with 5 Yagi-antenna array. We can get the position of the lightning in space by the phase bias caused by propagation from lightning to the different antenna. Finally, the three - dimensional distribution of lightning in space can be fully presented by using the interferometry antenna equation. Lightning usually occurs during rain, this study compares the data of Chung-Li VHF radar and C-POL radar, and finds that the frequency of lightning occurrence in different periods is related to the intensity of C-POL radar. After comparing the data of CWB、Chung-Li VHF radar and C-POL radar, it was found that the location of the lightning would move due to the drift of the thunderstorm, after further comparing the wind field obtained by WISSDOM with the speed of the thunderstorm, the result are not far behind.
Appears in Collections:	[Graduate Institute of Space Science] Department of Earth Sciences

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