不同GPS掩星电离层剖面产品相关性分析

Correlation analysis of ionospheric profiles for different GPS occultation missions

将在一定时空限定范围内的不同低轨卫星COSMIC、GRACE、CHAMP、FY3C的电离层掩星电子密度剖面定义为一个掩星对来对比分析不同类型掩星电离层产品。结果表明:COSMIC掩星对之间的电子密度剖面整体轮廓符合得很好,电子密度剖面主要在250 km以下和500 km以上存在较大的偏差,250~500 km的电子密度整体偏差较小,统计得到的COSMIC掩星对的电子密度参量Nm F2和hm F2的相关系数能分别达到0.99和0.97,具有高度相关性,不同COSMIC卫星之间没有明显的系统误差;COSMIC、GRACE、CHAMP和FY3C不同低轨卫星间的电子密度剖面略有差异,通过统计电子密度参量Nm F2和hm F2之间的相关系数,COSMIC和CHAMP的相关系数分别为0.95和0.86,COSMIC和GRACE的相关系数分别为0.98和0.94,COSMIC和FY3C的相关系数分别为0.96和0.92,不同掩星类型之间的电子密度参量之间也具有高度相关性,验证了不同卫星任务GPS掩星电离层剖面的一致性。

The occultation ionospheric electron density profile events obtained by low-orbit satellites COSMIC、GRACE、CHAMP and FY3 C are defined as an occultation pair in a certain range to analyze the different types of occultation ionospheric products. The results show that: the silhouette of the electron density profile between COSMIC occultation consistent well,there are big deviation under250 km and 500 km above,the deviation is small between 250 ~ 500 km,the correlation coefficient of Nm F2 and hm F2 can reach 0.99 and 0.97,there are no obvious bias between different COSMIC satellites. The electron density profile have different differences between LEO satellite. By calculating electron density parameters( Nm F2 and hm F2),the correlation coefficient of Nm F2 and hm F2 between the COSMIC and CHAMP are 0.95 and 0.86 respectively,the correlation coefficient between COSMIC and GRACE are 0.98 and 0.94,the correlation coefficient between COSMIC and FY3 C are 0.96 and 0.92. The electron density parameters of different occultation types also have high correlation which could validate the consistence of the GPS radio occultation profiles from different LEO satellite missions.