使用福爾摩沙衛星七號（福衛七號）TGRS酬載所提供之掩星剖線資料，觀察正負15°磁緯度附近之日間電離層之電子濃度，以研究赤道異常峰強度（電子濃度）、位置、高度及出現時間對磁偏角之響應。本研究挑選三個磁經度區域，分別代表正磁偏角（-100°至-40°，稱為D+）、負磁偏角（5°至65°，稱為D-）及零磁偏角（165°至-135°，稱為D0）。相較之下，正磁偏角區，南北半球之赤道異常強度最大、出現時間最早、位置最北、時間差最大，且最大時間差發生在六月、最小時間差發生在十二月。而其在北半球高度最高，南半球高度則最低。負磁偏角區南北半球之赤道異常出現時間最晚、時間差最小、位置較南、高度差最小，且在南半球高度最高。零磁偏角區南北半球之赤道異常強度最小、位置最南、高度差最大。而其出現時間、時間差及高度皆介於其他兩區之間。結果證實磁偏角顯著影響電離層赤道異常之強度、位置、高度及出現時間。;Characteristics of EIA (equatorial ionization anomaly) strength, location, appearance time, and altitude are investigated by means of the ionospheric electron density profiles obtained by TGRS (Tri-GNSS Radio occultation System) onboard FORMOSAT-7/COSMIC-2 (F7/C2). The characteristics over three geomagnetic longitudinal sectors with different magnetic declinations, "D+" the most positive-declination, -100°E to -40°E geomagnetic; "D-" the most negative-declination, 5°E to 65°E geomagnetic; "D0" around zero-declination, 165°E to -135°E geomagnetic, are examined. Results among the three sectors show that in D+, the northern and southern EIA crests yield the strongest strengths, appear at the earliest time, and move toward the most northern locations while the northern (southern) one reaches the highest (lowest) altitude. In D-, the two EIA crests yield the strengths and locations in-between those in D+ and D0, exhibit the latest appearance times while the southern one reaches the highest altitude. In D0, the EIA crests exhibit the weakest strengths, and move toward the most southern locations, appear at the time in-between the two other sectors, and have the largest altitude differences. The results show that declination is an important factor to the EIA crest characteristics.
