中緯度地區電離層散塊E層的不規則體主要是由梯度漂移不穩定的物理機制所引起，由頻譜上來看是屬於型態二的不規則體。 本研究是利用位於中緯度地區的中壢特高頻雷達，從1999年7月到2000年2月，以52MHz的發射頻率觀測3公尺左右結構的不規則體，針對所觀測的資料做分析，另外也分析1996年所觀測的資料，分析的內容包括：(1)利用雷達干涉法研究不規則體於空間中的漂移運動，(2)系統相位差的估計，(3)頻寬與平均都卜勒頻移的關係。另外亦提出以散塊漂移的理論來說明，在回波功率之高度-時間-強度(RTI)圖中呈線紋結構的準週期性回波(QP Echo)，是由場沿不規則體準週期性的漂入雷達體積所造成的現象。 The sporadic E irregularities associated with typeII radar spectra are mainly caused by gradient drift instability at mid-latitude ionospheric region. Employing the Chung-Li 52MHz radar, the observations of meter-scale irregularities were carried out from July, 1999 to February, 2000. In addition, the analysis of data taken in 1996 was also included in this study. The analysis include: (1) using radar interferometer to research the drift motions of irregularities (2) the estimation of system phase difference (3) relationships between spectral widths and mean doppler shifts. Futhermore, propose a possible mechanism to explain the quasi-periodic(QP) echoes that present the striated structures in the RTI plot, which is the phenomenon caused by field aligned irregularities drift into radar volume quasi-periodically.
