Athens地区电离层TEC、NmF2以及板厚

本文使用Athens站2001—2005年间电离层GPS/TEC和f_oF₂数据,分析了TEC、N_mF₂和电离层板厚τ日变化、季节变化特征以及与太阳活动的统计关系,得到以下结论:电离层TEC和N_mF₂具有相似的日变化特征,最大值出现在14∶00LT;TEC在2001和2002年白天出现"冬季异常"现象,N_mF₂在2001—2005年白天均出现该现象;电离层板厚τ主要分布在200~600 km,存在黎明峰和日落峰双峰结构,黎明峰一般出现在5∶00—6∶00LT,日落峰结构一般从日落后开始出现,在午夜前达到极大值;14∶00LT和2∶00LT时刻TEC、N_mF₂同太阳活动的关系呈现"线性"、"饱和"以及"放大"趋势,而τ则出现正、负及不明显的线性关系;最后,我们分析认为黎明峰归因于电离层TEC增加以及N_mF₂的减少,而日落峰主要是由TEC减少速度低于N_mF₂造成的.

Ionospheric TEC, NmF2 and slab thickness over the Athens region

The data of TEC, f_oF₂ obtained at the Athens station, from year 2001 to 2005, are used to analyze the diurnal, seasonal, and solar activity variations of TEC, N_mF₂ and slab thickness τ. The results reveal that TEC and N_mF₂ have similar diurnal variation patterns, and maximize at 14∶00LT. The "winter anomalies" of TEC occurred during daytime in year 2001 and 2002, while that of N_mF₂ occurred between 2001 and 2005. The τ values are about 200~600 km, and show double-peak structures including predawn and sunset peaks. The predawn peak appeared usually at 5∶00—6∶00LT, and the sunset peak began to appear after sunset, reaching the maximum value before midnight. The relationships between ionospheric TEC, N_mF₂ and solar activity show linear, saturation and amplification features, while τ had positive and negative linear variations or an unremarkable linear relationship. Finally, we suggest that the predawn peak is caused by the increased TEC and decreased N_mF₂, and the sunset peak can be attributed to the slower decrease for TEC than N_mF₂.