Quiet-condition variations in the scale height at F2-layer peak at Jicamarca during solar minimum and maximum

Abstract

Abstract. This study is the first attempt to examine the quiet-condition variations in scale height (Hm) near the F2-layer peak in the equatorial ionosphere. The data periods of Hm derived from the Jicamarca ionograms are JanuaryDecember 1996 and April 1999-March 2000. The results show that the greatest and smallest Hm values are generally at 11:00-12:00 LT and 04:00-05:00 LT, respectively. Additionally, the sunrise peak occurs at 06:00 LT only during solar minimum. The post-sunset peaks in the equinoctial and summer months are more obvious during solar maximum. The Hm difference between solar minimum and maximum are significant from afternoon to midnight. On the other hand, the Hm values during 07:00-10:00 LT for solar minimum are close to those for solar maximum. Furthermore, the correlation of Hm with the critical frequency (foF2) of F2-layer is generally low. In contrast, the correlation between Hm and the peak height (hmF2) of F2-layer is high. For Hm and the thickness parameter (B0) of F2-layer, the correlation between these two parameters is almost perfect.

Ionospheric effects on the F region during the sunrise for the annular solar eclipse over Taiwan on 21 May 2012

“…also indicated that the uplift in the hmF 2 was driven by the vertical drift. Furthermore, we examined the ionospheric scale height around the peak height (H m ), which was considered to be associated with the sunrise during the daytime (Lee and Reinisch, 2007). The result showed a small fluctuation between 06:00 LT and 07:00 LT and an apparent increase at 07:00 LT (Fig.…”

Vertical electron density and topside effective scale height (<I>H</I><sub>T</sub>) variations over the Indian equatorial and low latitude stations

“…3.2. Lee and Reinisch (2007) studied the diurnal and seasonal variations of the scale height (H m ) at the F2 layer peak over a dip equatorial station Jicamarca and indicated that the diurnal variations of H m generally show the greatest value at 11:00 to 12:00 LT and that these values at noon are greater in the equinoctial and winter months. Liu et al (2008) investigated the local time, seasonal, latitudinal and longitudinal variations of Vertical Scale Height (VSH) with the COSMIC radio occultation measurements during low solar activity period (2006)(2007)(2008) and reported that the VSH values are higher during day-time, compared to those in the night-time with an outstanding peak around local noon and decreasing after noon till mid night.…”

An analysis of the scale height at the F 2-layer peak over three middle-latitude stations in the European sector

“…Zhang et al, 2006;Lee and Reinisch, 2007;Nambala et al, 2008, among others) and they can be useful for obtaining information for the topside-profile formulation from bottomside measurements and modelling. However, further studies and analyses are needed to validate analytical functions relating to the topside and bottomside parameters in order to contribute to the IRI modelling.…”

“…Nsumei et al (2010) have evaluated the daily variations of the bottomside-derived H m at different latitudes, and have reported a latitude dependence in agreement with our current results. Moreover, the results reported by Zhang et al (2006), Lee and Reinisch (2007), and Nambala et al (2008), using data from Hainan (19.4 • N; 109.0 • E), Jicamarca (12.0…”

“…Many studies have dealt with an analysis of the variations of H m in recent years (e.g. Belehaki et al, 2006;Zhang et al, 2006;Lee and Reinisch, 2007;Mosert et al, 2007;Nambala et al, 2008). However, the databases used in most cases also enable an analysis of the diurnal and seasonal variations of H m at particular locations.…”