COSMIC掩星电子密度廓线的质量检核

Quality check of the ionospheric density profiles from COSMIC radio occultation observations

利用COSMIC掩星任务自2010年至2014年的电离层电子密度廓线,使用只考虑廓线自身特性的4种参数进行质量检核,并对廓线质量的时空分布进行分析。发现在廓线质量的空间分布上,廓线不合格率在高纬地区最高,其次是低纬地区,在中纬地区最低,这可能与电子密度分布在磁赤道附近存在赤道异常、两极地区的磁场强度最大有关。廓线质量的季节变化较明显,在南、北半球,冬、春两季的廓线不合格率均显著高于夏、秋两季。另外,廓线质量具有一定昼夜分布特性,不合格率白天明显较夜晚低,且在晨昏分界线上变化较大。合格廓线的电子密度峰值和峰值高度分布在磁赤道附近明显高于其他区域,呈现"双驼峰"现象。

With the ionospheric electron density profiles derived from the COSMIC radio occultation mission during 2010 to 2014,the qualities of these profiles were checked comprehensively using four quality control parameters which consider only the profile′s own characteristics.The spatial and temporal distributions of the qualities of the profiles were analyzed accordingly.It is found that the qualities of the profiles are the highest over the high-latitude regions,followed by the low-latitude regions and the lowest over the mid-latitude regions.This may be due to the existence of the equatorial anomaly of the electron density distribution near the magnetic equator.The seasonal variation of the qualities of the profiles is distinct,which shows a significantly higher rejection ratio in winter and spring than in summer and autumn over both of the two hemispheres.In addition,the rejection ratio of the profiles is significantly lower in daytime than in nighttime,and it has great changes occurring at twilight demarcations.The peak electron densities and the corresponding peak heights derived from the qualified profiles are significantly higher over magnetic equator than over other regions,which shows a“double hump”phenomenon.