中文摘要：

以全球无线电探空数据和美国环境预报中心（National Centers for Environmental Prediction，NCEP）预报模式为参照，对COSMIC数据分析与管理中心（COSMIC Data Analysis and Archive Center，CDAAc）提供的2007—06-01～2007—06—30的气象、电离层与气候星座观测系统（the constellation observing system for meteorology，Ionosphere，and climate，COSMIC）的GPS掩星折射指数廓线进行了统计验证。结果表明，掩星廓线的精度在高纬度地区最好，在低纬度地区最差。中、低纬度带掩星廓线相对于探空廓线有系统性相对偏差，该偏差在掩星廓线与NCEP预报廓线的比较中不存在，说明探空数据的质量是造成这种偏差的主要原因，这可能与不同地区所采用的无线电探空仪的性能有关。

英文摘要：

Refractivity profiles observed by COSMIC（the constellation observing system for meteorology, ionosphere, and climate） GPS RO（radio occultation） mission were validated with global radiosonde soundings. The COSMIC RO events that occur within 2 h and 300 km of radiosonde soundings were gotten during the period from June 1 to June 30, 2007 and more than 4 000 pairs of refractivity profiles were analyzed. The differences between the two types of refractivity profiles are the smallest in high latitude region and the largest in low latitude region. The same trend is also found in the comparisons between COSMIC RO and NCEP（National Centers for Environmental Prediction） refractivity profiles. We concluded that the precision of RO refractivity profiles is better in high latitude region than that of in low latitude region. There are systematic biases between RO and radiosonde refractivity profiles in middle and low latitude region. No systematic bias can be found in the comparison be tween the corresponding COSMIC RO and NCEP refractivity profiles. We deduced that the quality of radiosonde data could be the main reason for that bias.