Global 3‐D ionospheric electron density reanalysis based on multisource data assimilation
Global 3‐D ionospheric electron density reanalysis based on multisource data assimilation
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DOI：
10.1029/2012ja017968
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发表时间：
2012-09
影响因子：
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通讯作者：
X. Yue;W. Schreiner;Y. Kuo;D. Hunt;Wenbin Wang;S. Solomon;A. Burns;D. Bilitza;Jann‐Yenq Liu-Jann‐Yenq
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作者：
X. Yue;W. Schreiner;Y. Kuo;D. Hunt;Wenbin Wang;S. Solomon;A. Burns;D. Bilitza;Jann‐Yenq Liu-Jann‐Yenq
我们报告了2002-2011年基于多源数据同化的全球三维电离层电子密度再分析示范研究的初步结果。利用国际参考电离层（IRI） 2007模型和卡尔曼滤波技术，将平静日电离层数据同化到数据同化模型中，完成了每月全球电离层电子密度的再分析。这些数据包括全球导航卫星系统（GNSS）对地面站电离层总电子含量（TEC）的观测，CHAMP、GRACE、COSMIC、SAC-C、Metop-A和TerraSAR-X卫星对电离层无线电掩星的观测，以及Jason-1和2高度计TEC的测量。再分析的输出是三维网格电离层电子密度，时间和空间分辨率分别为世界时1小时、纬度5小时、经度10小时和海拔30公里。再分析结果的气候特征，如太阳活动依赖性、季节变化和电离层的全球形态，与经验模式和观测结果吻合得很好。利用国际GNSS服务全球电离层图的全球电子含量、2007-2010年扑克平面非相干散射雷达观测到的电子密度剖面和2002-2011年全球电离层探测网络观测到的foF2对再分析方法进行了验证。所有的比较都表明，与IRI-2007的预测相比，重新分析的偏差和偏差更小。特别是在2006年4月6颗COSMIC卫星发射后，再分析显示比IRI预测有显著改善。IRI模式在23/24太阳极小期对低纬度电离层F区密度的明显高估得到了较好的修正。讨论了再分析的应用前景和改进方法。
[1] We report preliminary results of a global 3-D ionospheric electron density reanalysis demonstration study during 2002–2011 based on multisource data assimilation. The monthly global ionospheric electron density reanalysis has been done by assimilating the quiet days ionospheric data into a data assimilation model constructed using the International Reference Ionosphere (IRI) 2007 model and a Kalman filter technique. These data include global navigation satellite system (GNSS) observations of ionospheric total electron content (TEC) from ground-based stations, ionospheric radio occultations by CHAMP, GRACE, COSMIC, SAC-C, Metop-A, and the TerraSAR-X satellites, and Jason-1 and 2 altimeter TEC measurements. The output of the reanalysis are 3-D gridded ionospheric electron densities with temporal and spatial resolutions of 1 h in universal time, 5 in latitude, 10 in longitude, and 30 km in altitude. The climatological features of the reanalysis results, such as solar activity dependence, seasonal variations, and the global morphology of the ionosphere, agree well with those in the empirical models and observations. The global electron content derived from the international GNSS service global ionospheric maps, the observed electron density profiles from the Poker Flat Incoherent Scatter Radar during 2007–2010, and foF2 observed by the global ionosonde network during 2002–2011 are used to validate the reanalysis method. All comparisons show that the reanalysis have smaller deviations and biases than the IRI-2007 predictions. Especially after April 2006 when the six COSMIC satellites were launched, the reanalysis shows significant improvement over the IRI predictions. The obvious overestimation of the low-latitude ionospheric F region densities by the IRI model during the 23/24 solar minimum is corrected well by the reanalysis. The potential application and improvements of the reanalysis are also discussed.