A comparison of ionospheric O+/light‐ion transition height derived from ion‐composition measurements and the topside ion density profiles over equatorial latitudes
A comparison of ionospheric O+/light‐ion transition height derived from ion‐composition measurements and the topside ion density profiles over equatorial latitudes
复制标题
DOI：
10.1029/2010gl045199
复制
发表时间：
2010-10
影响因子：
5.2
通讯作者：
S. Tulasi Ram;C. Liu;S. Su;R. Heelis
中科院分区：
文献类型：
--
作者：
S. Tulasi Ram;C. Liu;S. Su;R. Heelis
首次对直接（离子成分测量）和间接（从顶面离子密度分布）方法进行了比较研究，以确定赤道纬度上的O+/轻离子跃迁高度。从离子组成确定的过渡高度遵循类似的纬度和当地时间变化，作为F区电离层中的赤道电离异常（EIA）。南北半球离子组成的过渡高度的不对称性与夏季到冬季的半球间中性风模式一致。另一方面，由离子密度剖面得到的跃迁高度主要受赤道处垂直E × B漂移和顶侧电离层中陡峭的垂直离子密度梯度引起的标度高度（形状）变化的影响。因此，与赤道纬度的直接离子组成测量相比，从顶侧剖面得出的过渡高度系统性地较低，并显示出不一致的纬度和当地时间变化。
A comparative investigation is made, for the first time, of direct (ion‐composition measurements) and indirect (from topside ion density profiles) methods to determine the O+/light‐ion transition height over equatorial latitudes. The transition height determined from the ion‐composition follows similar latitudinal and local time variations as the underlying Equatorial Ionization Anomaly (EIA) in the F‐region ionosphere. The north‐south hemispheric asymmetries in the transition height from ion composition are consistent with the summer‐to‐winter interhemispheric neutral wind patterns. On the other hand, the transition height derived from ion density profiles is chiefly influenced by changes in the scale height (shape) due to vertical E × B drift at the equator and steep vertical ion density gradients in topside ionosphere. As a result, the transition height derived from topside profiles are systematically lower and exhibit inconsistent latitudinal and local time variations when compared to direct ion‐composition measurements at equatorial latitudes.