Analysis of the temporal-spatial distribution of ionosphere scale height based on COSMIC occultation data

In this study, the distribution characteristics of scale height at various solar activity levels were statistically analyzed using the Constellation Observing System for Meteorology, Ionosphere, and Climate (COSMIC) radio occultation data for 2007–2013. The results show that: (1) in the mid-high latitude region, the daytime (06–17LT) scale height exhibits annual variations in the form of a single peak structure with the crest appearing in summer. At the high latitude region, an annual variation is also observed for nighttime (18–05LT) scale height; (2) changes in the spatial distribution of the scale height occur. The crests are deflected towards the north during daytime (12–14LT) at a geomagnetic longitude of 60°W–180°W, and they are distributed roughly along the geomagnetic equator at 60°W–180°E. In the approximate region of 120°W–150°E and 50°S–80°S, the scale height values are significantly higher than those in other mid-latitude areas. This region enlarges with increased solar activity, and shows an approximately symmetric distribution about 0° geomagnetic longitude. Nighttime (00–02LT) scale height values in the high-latitude region are larger than those in the low–mid latitude region. These results could serve as reference for the study of ionosphere distribution and construction of the corresponding profile model.