摘要
利用我国9个电离层观测站第21和22太阳周大约20年的foF2月中值数据,分析太阳活动和地磁活动对电离层foF2的影响,结果显示白天和夏季夜间foF2和太阳黑子数R之间存在着明显非线性关系,并且随着纬度的降低逐渐增强.当回归分析加入地磁Ap指数时,多重回归模型与实测值误差进一步减小,说明同时考虑太阳活动和地磁活动的非线性影响能够更好地描述foF2的变化.基于foF2与太阳黑子数R及地磁指数Ap之间的非线性统计关系,利用Fourier级数建立9个单站谱模型,并与国际参考电离层IRI进行了比较,精度有一定提高.
The hourly values of the critical frequency of ionospheric F region, foF2, observed at nine ionosonde stations in China about two solar cycles have been used to investigate the dependence of the monthly median foF2 on solar activity and geomagnetic activity, and to construct a single-station model （SSM） using Fourier expansion. The results of the present analysis show that there is a significant nonlinear relationship between monthly median foF2 and sunspot number R especially at daytime in each month and nighttime in summer and the nonlinear relationship is more evident as the latitude decreases. Furthermore, introducing geomagnetic index Ap further improves the description of variation of monthly median foF2, and the standard deviations decrease also dependently on time and month. Based on the nonlinear relationships, we develop a new SSM for the selected stations and the SSMs are compared with IRI, which shows a much better agreement with observations.
出处
《地球物理学报》
SCIE
EI
CAS
CSCD
北大核心
2008年第5期1296-1303,共8页
Chinese Journal of Geophysics
基金
自然科学重大国际合作项目(40310223)
电波环境特性及模化技术国家重点实验室项目(9140C0801060803)共同资助
关键词
太阳循环变化
单站模型
foF2月中值
太阳黑子数
Solar cycle variation, Single-station model, Monthly median foF2, Sunspot numbers
