| 摘要: | 本論文利用高頻都卜勒探測系統觀察2021年9月10-14日燦樹強烈颱風與2022年3月6-7日鋒面引發之移行電離層擾亂。利用快速傅立葉轉換計算擾亂期間特徵週期，並使用互相關分析與來向角分析推估擾亂時間差及擾亂來向，藉此，探討擾亂訊號特徵以及事件之擾亂源頭相關性。研究發現於2021年9月11日0600 LT當颱風外圍即將觸及臺灣時，都卜勒頻移擾亂會出現約為15分鐘之週期波動，其波長為140 km；該波動之水平傳播速度為155-158 m/s，其方向與颱風眼方位角相差6.9-9 °，此說明波動可能來自颱風中心。進一步研究發現波動之垂直傳播速度為向上170-194 m/s，而使用群相速計算驗證之結果為向上110-165 m/s，兩者數據相近。鋒面於2022年3月6日2000 LT亦會引發明顯都卜勒頻移擾亂。研究結果顯示其水平傳播速度為180-181 m/s，其方向與鋒面波前方向相差26 °，而垂直傳播速度則向下143 m/s，與颱風垂直傳播方向相反。;This study used a high-frequency Doppler system to observe traveling ionospheric disturbances caused by Typhoon Chanthu during September 10-14, 2021, and the front on March 6-7, 2022. The disturbances were analyzed using Fast Fourier Transform (FFT), cross-correlation analysis, and Arithmetic Optimization Algorithm (AOA) analysis to investigate their correlation with the events. The results revealed that on September 11, 2021, at 0600 LT, as the typhoon approached Taiwan, disturbances with a 15-minute periodicity, 140 km wavelength, and a horizontal propagation velocity of 155-158 m/s were observed. The disturbances exhibited a deviation angle of 6.9-9 ° from the typhoon′s eye position, suggesting a connection with the typhoon. The vertical propagation velocity of the disturbances was upward, ranging from 170-194 m/s, using group and phase velocity calculation for validation, it indicates the speed of 110-165 m/s in the upward direction. The data from both methods show similar values. Furthermore, on March 6, 2022, at 2000 LT, the front caused significant Doppler frequency shift disturbances. These disturbances had a horizontal propagation velocity of 180-181 m/s, with a deviation angle of 26 ° from the center of the front. The vertical propagation velocity was downward at 143 m/s, opposite to the vertical propagation of the typhoon. In conclusion, the findings established a correlation between the disturbance signals and the respective events. |
