Evaluation of the orbit altitude electron density estimation and its effect on the Abel inversion from radio occultation measurements
Evaluation of the orbit altitude electron density estimation and its effect on the Abel inversion from radio occultation measurements
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DOI：
10.1029/2010rs004514
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发表时间：
2011-02
期刊：
影响因子：
1.6
通讯作者：
X. Yue;W. Schreiner;C. Rocken;Y. Kuo
中科院分区：
文献类型：
--
作者：
X. Yue;W. Schreiner;C. Rocken;Y. Kuo
本文利用CHAMP射电掩星（RO）和平面朗缪尔探测器（PLP）2002-2008年的观测以及气象电离层和气候星座观测系统（COSMIC）2007.090-2007.120的观测来评估轨道高度电子密度估计及其对RO测量阿贝尔反演的影响。 CHAMP 上 PLP 观测值与 RO 估计轨道电子密度的比较表明，RO 估计往往高估真实轨道电子密度，平均高估 10%。平均相对偏差约为20%，并随着电离层峰高和卫星轨道的增加而略有减小。它在夜间比白天更大，并且在日出时达到顶峰。利用NeQuick模型对COSMIC观测进行的模拟表明，太阳活动和卫星轨道高度变化不会影响成功反演的电子密度剖面与观测掩星事件的比率以及电子密度的相对阿贝尔反演误差。不同的轨道电子密度推导方法，包括通过独立的轨道观测给出的 RO 总电子含量估计，并假设等于最高点，对阿贝尔反演电子密度没有本质影响。增加在轨观测甚至会对阿贝尔反演轨道高度周围的电子密度产生负面影响，这与我们的想象相反。
In this paper, the observations from CHAMP radio occultation (RO) and Planar Langmuir Probe (PLP) during 2002–2008 and Constellation Observing System for Meteorology Ionosphere and Climate (COSMIC) observations during 2007.090–2007.120 are used to evaluate the orbit altitude electron density estimation and its effect on the Abel inversion from RO measurements. Comparison between PLP observed and RO estimated orbit electron density on board CHAMP shows that RO estimation tends to overestimate the true orbit electron density by 10% averagely. The average relative deviation is ∼20% and decreases slightly with the increase of the ionospheric peak height and the satellite orbit. It is larger at nighttime than daytime and peaks around sunrise time. Simulations based on COSMIC observations using NeQuick model indicate that the solar activity and the satellite orbit altitude variations will not influence the ratio of the successfully retrieved electron density profiles to the observed occultation events and the relative Abel inversion error of the electron density as well. Different orbit electron density derivation methods, including estimation by the RO total electron content, given by an independent on orbit observation, and assumed to be equal to the topmost point, will have no essential influence on the Abel retrieved electron density. Adding an on orbit observation even has a negative effect on the Abel retrieved electron density around the orbit altitude, which is contrary to our imagination.