使用COSMIC掩星和垂测仪，探测2011-2012年北京地区电离层临界频率数据，比较不同探测手段获取的电离层特征参量随地方时和地磁季节相关性的变化。研究表明：2组数据具有较好的相关性；标准偏差随地方时变化，日出时6：00 LT开始增大，日落时16：00LT到次高值，19：00LT达最大值后开始下降；标准偏差随地磁季节变化，夏季最小，冬季最大。分析认为，电子密度在垂直和水平方向上的梯度变化，造成掩星反演误差增大，可能导致了数据相关性在不同地磁季节和地方时刻的相应变化。
In this paper, foF2 data obtained by COSMIC radio occultation is compared to Beijing ionosonde observation station during 2 years from January 2011 to December 2012. The correlation coefficient and the standard deviation of the observation data obtained by two techniques are calculated and the variations of foF2 difference with local time and geomagnetic season are analyzed. The results show that the correlation of foF2 is good. The standard deviation of foF2 begins to increase from local time of 6:00 at sunrise. It reaches the second peak at local time of 16:00 at sunset. It reaches the highest at local time of 19:00 and then begins to decrease. The standard deviation of foF2 is lower in the geomagnetic summer and is larger in the geomagnetic winter. The gradient of the electron density in the vertical and horizontal directions may increase the error of occultation inversion, which may lead to the corresponding changes of the data correlation in different geomagnetic seasons and local time.
2017,38(3): 76-80 收稿日期：2017-05-16
DOI：10.3969/j.issn.1003-3246.2017.03.013
基金项目：中央公益性科研院所基本科研业务（项目编号：No.DQJB16B08）
作者简介：马新欣(1983-),女,博士,助理研究员,主要从事电离层数据分析工作。E-mail:maxinxin0923@163.com.
参考文献：
郭鹏, 洪振杰, 张大海. COSMIC 计划[J]. 天文学进展, 2002, 20(4):324-336.
黄智, 袁洪. 磁赤道地区 2007-2013 年 COSMIC 掩星反演和国际参考电离层模型输出结果分析[J]. 地球物理学报, 2016, 59(7):2 333-2 343.
金亚奇, 张东和, 刘玉梅, 等. 不同太阳活动条件下电离层形态对估算 GPS 系统硬件延迟的影响[J]. 空间科学学报, 2013, 33(4):427-435.
孙凌峰, 赵必强, 乐新安, 等. 中国区域电离层垂测仪探测参量与 COSMIC 掩星反演结果比较研究[J]. 地球物理学报, 2014, 57(11):3 625-3 632.
Chun Y J, Lee C C, Chen W S, et al. Comparison between bottom side ionospheric profile parameter sretrieved from FORMOSAT3
measurement sand ground-based obseratons collected at Jicamarca[J]. Journal of Atmospheric and Solar-Terrestrial Physics, 2011, 73(13):1 665-1 673.
Ely C V, Batista I S, Abdu M A. Radio occultation electron density profiles from the FORMOSAT-3/COSMIC satellites over the Brazilian region:A comparison with Digisonde data[J]. Advances in Space Research, 2012, 49(11):1 553-1 562.
Hu L H, Ning B Q, Liu L B, et al. Comparison between ionospheric peak parameters retrieved from COSMIC measurement and ionosonde observation over Sanya[J]. Advances in Space Research, 2014, 54(6):929-938, doi:10.1016/j.asr.2014.05.012.
Kelley M C, Wong V K, Aponte N, et al. Comparison of COSMIC occultation-based electron density profiles and TIP observations with Arecibo incoherent scatter radar data[J]. Radio Science, 2009, 44(4):RS4011, doi:10.1029/2008RS004087.
Krankowski A, Zakharenkova I, Krypiak-Gregorczyk A, et al. Ionospheric electron density observed by FORMOSAT-3/COSMIC over the European region and validated by ionosonde data[J]. Journal of Geodesy, 2011, 85(12):949-964.
Lei J H, Syndergaard S, Burns A G, et al. Comparison of COSMIC ionospheric measurements with ground-based observations and model predictions:preliminary results[J]. Journal of Geophysical Research, 2007, 112(A7):A07308, doi:10.1029/2006JA012240.
Li L X, Zhang D H, Zhang S R, et al. Influences of the day-night differences of ionospheric variability on the estimation of GPS differential code bias[J]. Radio Science, 2015, 50(4):339-353.
Sahai Y, de Jesus R, Fagundes P R, et al. Effects observed in the equatorial and low latitude ionospheric F-region in the Brazilian sector during low solar activity geomagnetic storms and comparison with the COSMIC measurements[J]. Advances in Space Research, 2012, 50(10):1 344-1 351.
Schreiner W S, Sokolovskiy S V, Rocken C, et al. Analysis and validation of GPS/MET radio occultation data in the ionosphere[J]. Radio Science, 1999, 34(4):949-966.
Straus P R. Ionospheric climatology derived from GPS occultation observations made by the ionospheric occultation experiment[J]. Advances in Space Research, 2007, 39(5):793-802.
Wu X C, Hu X, Gong X Y, et al. Analysis of inversion errors of ionospheric radio occultations[J]. GPS Solutions, 2009, 13(3):231-239.
Wu X C, Hu X, Gong X Y, et al. An asymmetry correction method for ionospheric radio occultation[J]. Journal of Geophysical Research, 2009, 114(A3):A03304, doi:10.1029/2008JA013025.
Zhang D H, Shi H, Jin Y Q, et al. The variation of the estimated GPS instrumental bias and its possible connection with ionospheric variability[J]. Science China Technological Sciences, 2014, 57(1):67-79.
