本論文研究地球磁場及電離層於2000年4月6日磁暴期間的變化情形。地磁變化主要是地磁指數Kp與Dst。電離層變化則分析中壢及武漢電離層探測儀(Ionospheric sounder)所記錄的電離層圖,利用各站觀測電離層圖中固定頻率之虛高,計算其垂直方向之群速及相速。探討相速及兩站之間的相位關係可獲知水平波動傳播。資料結果顯示其垂直相速及群速傳輸,分別向上及向下,因此波動能量為向上傳播。將垂直相速投影在水平面時之速度,發現它們與兩站之間的相速傳播相同,其為北向南160m/s,而且高度約在200公里。此一現象乃是磁暴日時,高緯度因光能及熱能的加溫作用,形成一個由高緯度向低緯度傳播的移行大氣擾動之特性。 The great magnetic storm of April 6-7, 2000 generated ionospheric disturbances in the west Pacific region. Two ionosondes at Wuhan (30.6°N, 114.4°E) and Chung-Li (24.9°N, 121°E) observed the ionosphere during this period. The variations of the ionospheric parameters, foF2 and h’F, show that the traveling atmospheric disturbances (TADs) affect the ionosphere at middle and low latitudes. The meridional velocity has been deduced from the time delay of h’F recorded at the two stations. Furthermore, a method of deriving the vertical phase and group velocities is applied to the sequences of virtual heights at fixed sounding frequencies. The agreement between the meridional and vertical velocities demonstrates that the upward motions of the ionospheric plasma are caused by the TADs.