电离层小尺度因素对无线电大气掩星弯曲角的影响  

Effect of ionospheric irregularity on GNSS atmospheric radio occultation bending angle

作　　者：李明哲 乐新安[1,2,3,4] LI Mingzhe;YUE Xin’an(Key Laboratory of Earth and Planetary Physics,Institute of Geology and Geophysics,Chinese Academy of Sciences;Innovation Academy for Earth Science,Chinese Academy of Sciences;Beijing National Observatory of Space Environment,Institute of Geology and Geophysics,Chinese Academy of Sciences;College of Earth and Planetary Sciences,University of Chinese Academy of Sciences:Beijing 100029,China)

机构地区：[1]中国科学院地质与地球物理研究所地球与行星物理重点实验室 [2]中国科学院地球科学研究院 [3]中国科学院地质与地球物理研究所北京空间环境国家野外观测研究站 [4]中国科学院大学地球与行星科学学院,北京100029

出　　处：《航天器环境工程》2021年第3期318-327,共10页Spacecraft Environment Engineering

基　　金：中国科学院重大科技基础设施开放研究项目“基于子午工程的中低纬大气层‒电离层的相互作用研究”。

摘　　要：历经25年的发展,基于GNSS的无线电掩星技术已经成为一种有效的临近空间探测手段,但是在无线电大气掩星观测及数据处理过程中不可避免地会受到各种误差的影响,其中,电离层是重要误差源之一。由于电离层小尺度因素的存在,GNSS信号在穿越电离层过程中会受到影响,表现为振幅和相位上的振荡,并最终影响反演所得的大气弯曲角产品。文章基于COSMIC大气弯曲角数据,研究电离层小尺度因素中扩展E层(Es层)及F层不均匀体在中低纬地区对无线电大气掩星的影响,通过计算不同高度区间内的弯曲角偏差标准差统计研究电离层Es层及F层不均匀体发生率与大气弯曲角振荡的关系。结果表明,Es层及F层不均匀体能够引起大气弯曲角振荡,表现出弯曲角随纬度、磁地方时及季节变化的特性,且这些电离层小尺度因素能够影响到的高度区间为35~80 km。该研究有助于进一步认识电离层小尺度因素对GNSS无线电大气掩星探测技术的影响,以及后续提高大气掩星产品的数据质量。With the development in the past 25 years,the Global Navigation Satellite System(GNSS)atmospheric radio occultation(RO)has been found to be an effective method to detect the near Earth’s space environment.Even though the quality of the RO products is high,the bias still exists and could be reduce the effectiveness of tbe RO,especially,the ionospheric effect on the atmospheric RO.The GNSS signal is affected by the ionospheric irregularity,including the sporadic E(Es)and the F region irregularity,in terms of the oscillations of the amplitude and the phase.This effect could reduce the quality of the atmospheric RO products.In this study,based on the data of the Constellation Observing System for Meteorology,Ionosphere,and Climate(COSMIC)RO,the bending angle oscillation,which is defined as the standard deviation of the bias between the observed bending angle and that obtained with the climatology model of the National Center for Atmospheric Research(NCAR),is used for the statistical analysis.The bending angle oscillation in different altitude intervals is studied.It is found that the bending angle oscillation shows significant variations in the latitude,the longitude,and the local time,which is well consistent with the Es and F layer irregularity occurrence features.Besides,the oscillation related to the ionospheric irregularity effect can be observed from 35 km to 80 km in the bending angles.A better understanding of these effects could benefit both the data retrieval and the applications of the RO in the lower atmosphere.

关 键 词：全球卫星导航系统 大气掩星 弯曲角 电离层小尺度因素 

分 类 号：V419.2[航空宇航科学与技术—航空宇航推进理论与工程] P352.3[天文地球—空间物理学]