摘要
利用1969—1980年期间东亚和澳大利亚扇区不同地磁纬度11个台站的电离层垂直探测数据,采用带通滤波的方法,分析了白天N_mF_2的准27天变化特征及其与太阳活动指数F_(10.7)的相关关系。结果表明,在大多数年里,太阳活动指数F_(10.7)和N_mF_2的短周期(2～70天)频谱中,27天周期附近都出现明显的极大值;在27天波段,F_(10.7)和N_mF_2的标准偏差有逐年变化特征,F_(10.7)的平均标准偏差为10.9%,N_mF_2的标准偏差随地磁纬度变化,赤道地区最小,纬度越高标准偏差越大,11个站的平均标准偏差为8.2%;在27天波段,N_mF_2与F_(10.7)存在显著的相关,在0.05的显著水平下,显著相关的概率在90%以上;N_mF_2相对于F_(10.7)的准27天变化平均滞后2天左右;从总体上看,太阳EUV辐射的准27天变化是造成N_mF_2准27天变化的主要原因。
The data observed at 11 ionosonde stations in the East Asia/Australia sector during 1969--1980 and the band-pass filter method have been used to analyze the characteristics of the quasi-27-day variations of daytime NmF2 and the relativity between NmF2 and the solar activity index F10.7. The results are summarized as follows. In most years, the short period （2-70 days） spectra of F10.7 and NmF2 have obvious maxima around 27-day period. In the quasi-27-day variations, the standard deviations of F10.7 and NmF2 have evident variability year-to-year. The average standard deviation of F10.7 is 10.9%. The standard deviations of NmF2 depend on geomagnetic latitude, the minima appear at equator and they become greater with increasing latitude. The average standard deviation of NmF2 of 11 stations is about 8.2%. In the quasi-27-day band, F10.7 and NmF2 have notable correlation. The probability of the significant correlation at 0.05 significance level exceed 90%. The average time delay between variations of the NmF2 and F10.7 is about 2 days.As a whole, the quasi-27-day variations of NmF2 primarily attribute to the quasi-27-day variations of the solar EUV flux.
出处
《空间科学学报》
CAS
CSCD
北大核心
2009年第4期368-376,共9页
Chinese Journal of Space Science
基金
国家自然科学基金项目(40621003)
国家重点基础研究规划项目(2006CB806306)共同资助
