Climatology of the ionospheric slab thickness along the longitude of 120° E in China and its adjacent region during the solar minimum years of 2007–2009

• Main Authors: Z. Huang, H. Yuan
• Format: Article
• Language: English
• Published: Copernicus Publications 2015-10-01
• Series: Annales Geophysicae
• Online Access: https://www.ann-geophys.net/33/1311/2015/angeo-33-1311-2015.pdf

The ionospheric slab thickness is defined as the ratio of the total electron content (TEC) to the ionospheric F2 layer peak electron density (<i>Nm</i>F2). In this study, the slab thickness is determined by measuring the ionospheric TEC from dual-frequency Global Positioning System (GPS) data and the <i>Nm</i>F2 from the Constellation Observing System for Meteorology, Ionosphere and Climate (COSMIC). A statistical analysis of the diurnal, seasonal and spatial variation in the ionospheric slab thickness is presented along the longitude of 120° E in China and its adjacent region during the recent solar minimum phase (2007–2009). The diurnal ratio, defined as the maximum slab thickness to the minimum slab thickness, and the night-to-day ratio, defined as the slab thickness during daytime to the slab thickness during night-time, are both analysed. The results show that the TEC of the northern crest is greater in winter than in summer, whereas <i>Nm</i>F2 is greater in summer than in winter. A pronounced peak of slab thickness occurs during the post-midnight (00:00–04:00 LT) period, when the peak electron density is at the lowest level. A large diurnal ratio exists at the equatorial ionization anomaly, and a large night-to-day ratio occurs near the equatorial latitudes and mid- to high latitudes. It is found that the behaviours of the slab thickness and the F2 peak altitude are well correlated at the latitudes of 30–50° N and during the period of 10:00–16:00 LT. This current study is useful for improvement of the regional model and accurate calculation of the signal delay of radio waves propagating through the ionosphere.