發生在電離層E 層中的電漿密度不規則體主要是沿著週圍地球磁力線方向沿長排列的。這種非均向特徵的理由緣自於平行與垂直於地球磁力線方向的粒子移動率相差非常得大。也由於這種非均向的特徵本身嚴格地限制觀測的進行。這種困難巳經可以利用雷達干涉法有效地來解決。這個子計畫的目的之一就是利用Huang et al.(1995)所發展出來的方法來測量平行及垂直於地球磁力線方向的方向角，特別是在較低的E 層中，值得注意的一點是，這個定量的數據至今並未發表在任何文獻上，當然包括巳被密集研究過的磁赤道地區。本子計畫在三年中將進行長期及密集的觀測。第一年計畫將執行特高頻雷達的密集探測，資料的篩選，以及引用上述分析技術來作初步的資料分析。第二年將與子計畫(一)舉行聯合觀測及建立資料庫。所有資料的來源，如子計畫(六)及子計畫(七)，將與本子計畫統合以利統計結果的分析與研究，這將在第三年的研究計畫中完成。在最近所發表的論文中談到導致準週期性回波(QP echoes)的可能機制(Tsunoda et al., 2004)。在這年的計畫當中，亦將使用中壢特高頻雷達與即將建構完成的30MHz 雷達執行聯合觀測來測試此機制的可能性。此兩雷達體積將呈東南與西北連線並且相隔大約250 公里。我們深深期待這個重要計畫的執行能夠更加瞭解準週期性回波。 Plasma density irregularities occurring in the ionospheric E-region are highly elongated in the ambient geomagnetic field direction. The reason for this anisotropy characteristic is the existence of large disparities between the parallel and cross-field mobilities. It is also the anisotropy itself that has seriously prohibited the measurements. This difficulty has been satisfactorily attacked with employing radar interferometry. One purpose of this project is to use the method developed by Huang et al. (1995) to measure the aspect angle and orthogonal angular width, special in the lower E-region. It is more important to note that these quantitative measurements have not yet been reported even for the equatorial regions in which the experiments have been intensively conducted. For purpose of data quality control, long-term and intensive observations will be conducted in the three years project. Intense operation of VHF radar, selection of available data, and primary analysis using the method mentioned above will be finished in the first year. Campaign observations with project (1) and creation of database will be held in the second year project. Combination of data from project (6) and project (7) in order to analyze and study the statistical results of aspect sensitivity will be completed in the third year. In this project campaign observations of the Chung-Li 52 MHz radar and a new 30 MHz radar will also be used to pursue the possible mechanism associated with the quasi-periodic echoes, proposed recently by Tsunoda et al. (2004). It is highly expected that the observational results can be satisfactorily understood by mean of the execution of this important project. 研究期間：9408 ~ 9507
