基于COSMIC数据电离层电子密度空间分布变化

Spatial Distribution Variations of Ionospheric Electron Density Based on COSMIC Data

天基GPS探测可以提供分布全球、高精度、高垂直分辨率的电离层观测资料,弥补地基GPS探测受地域限制、垂直分辨率低的问题.利用COSMIC掩星2008—2011年数据,网格化统计分析了太阳活动处于不同水平下的电子密度空间分布变化,以期为分析电离层电子密度的空间扰动变化提供参考背景.研究表明,电子密度存在明显赤道异常和威德尔海异常现象,并发现随太阳活动性增强,在250~350km高度范围电子密度赤道异常现象扩展到中纬地区,在300~500km高度范围威德尔海异常现象不仅发生在南半球夏季,春秋季电子密度夜间值比白天也显著增强;在250~500km高度范围,电子密度存在明显的威德尔海异常现象,并随着太阳活动性增强,异常区域地理范围扩宽.

Space-based GPS detection can provide the global distribution, high accuracy, high vertical resolution of the iono- sphere observation data, compensate for the problem of regional restriction and low vertical resolution in ground-based GPS de- tection. To enrich the relevant research, this study analyses the spatial distribution variation of electron density based on COS- MIC occultation data from 2008--2011 by statistical method. Results show that electron density is dominated by the EIA and WSA. With the solar activity enhancement, EIA extends into the middle latitudes from 250 km to 350 km height range, and WSA occurs not only in summer of the southern hemisphere, but also in spring and autumn there while electron density values during night time are greater than those during daytime from 300 km to 500 km height range; The electron density has obvious WSA phenomenon from 250 km to 500 km height range. And with the solar activity enhancement, the geographic range of ab- normal regional expands.