GNSS掩星大气参数反演中电离层残差模拟研究

发布时间：2018-05-29 04:51

本文选题：GNSS + 掩星　；参考：《中国矿业大学》2013年博士论文

【摘要】：GNSS掩星大气探测技术已广泛应用于数值天气预报和全球气候监测中。电离层是掩星大气探测的主要误差源之一，双频弯曲角线性组合法是目前应用最广泛的电离层误差改正方法。由于GNSS信号传播路径的弯曲分离和电离层高阶项的影响，经该方法改正后，反演大气参数中仍含有电离层残余误差。电离层残余误差是GNSS掩星反演中高层大气参数的主要误差。最大限度地降低电离层残余误差有利于实现GNSS掩星中高层大气高精度观测。弯曲角电离层残余误差的定性和定量研究对发展新的电离层误差改正方法意义重大。用ECMWF大气模式和COSMIC数据，对比分析了太阳活动“宁静”期和太阳活动“活跃”期弯曲角误差特性。结果表明，太阳活动“活跃”期弯曲角标准偏差较大；平均偏差与“宁静”期相比具有明显的“负值趋向性”；电离层残余误差对平流层顶部（35~50km）和中间层底部（50~65km）弯曲角影响显著。以MSIS90大气模式和3D NeUoG电离层模式为大气背景，模拟分析了不同电离层条件下掩星事件的弯曲角电离层残差。结果表明：弯曲角电离层残差是中间层和平流层顶部掩星大气反演参数的主要误差，其大小与太阳活动强度、地方时、掩星平面方位角密切相关。电离干扰会使弯曲角电离层残余误差增大数倍至二十多倍。量化研究了平流层底部（15~35km）、平流层顶部（35~50km）、中间层底部（50~65km）和中间层顶部（65~80km）的区域日平均弯曲角电离层残余误差。以MSIS90大气模式和3D NeUoG电离层模式为大气背景，用GPS/MetOp-A真实轨道数据仿真模拟了2008年7月15日全天的掩星事件。弯曲角电离层残余误差分析过程中，全球被划分为GLO (global)、NHH (north hemisphere high latitude)、NHM (north hemisphere middle latitude)、EDT (equatorial day time)、SHM (southhemisphere middle latitude)和SHH (south hemisphere high latitude)六个统计区域。分析了太阳活动强度、纬度带和电离层局部球对称对弯曲角电离层残差的影响。结果表明：弯曲角电离层平均偏差是一种负的系统性偏差，且随太阳活动强度的增强而增大。六个统计区域中，EDT的弯曲角电离层偏差最大，中间层顶部、中间层底部和平流层顶部的弯曲角电离层残差平均偏差分别可达0.048μrad、0.041μrad和0.032μrad；SHH的弯曲角电离层残差平均偏差最小，其大小几乎为零。弯曲角电离层残余误差的量化研究对中高层大气弯曲角电离层残余误差的建模和修正有一定的参考价值。用三维射线追踪法模拟分析了弯曲角电离层残差的产生机理，并对印度洋区域的电离层残差异常现象进行了初步分析。结果表明，，“入射线”和“出射线”的电子密度分布不对称是弯曲角电离层误差异常的主要原因。
[Abstract]:GNSS occultation atmosphere detection technology has been widely used in numerical weather forecasting and global climate monitoring. The ionosphere is one of the main error sources in occultation atmosphere detection. The double frequency bending angle linear combination method is the most widely used method to correct the ionospheric errors. Because of the bending separation of the GNSS signal propagation path and the influence of the ionospheric higher order term, the residual ionospheric error is still found in the inversion atmospheric parameters after the correction of the method. The ionospheric residual error is the main error of GNSS occultation inversion. Minimizing the residual ionospheric errors is beneficial to the realization of high accuracy GNSS occultation in the upper atmosphere. The qualitative and quantitative study of the residual errors in the curved ionosphere is of great significance to the development of new methods for correcting the ionospheric errors. Based on ECMWF atmospheric model and COSMIC data, the error characteristics of bending angle in the "quiet" period of solar activity and the "active" period of solar activity are compared and analyzed. The results show that the standard deviation of bending angle in the "active" period of solar activity is larger, the average deviation is more "negative tendency" than that in the "quiet" period. The residual ionospheric errors have a significant effect on the bending angles of the stratospheric top (35 ~ 50km) and the bottom of the interlayer (50- 65km). Taking the MSIS90 atmospheric model and 3D NeUoG ionospheric model as the atmospheric background, the curved angle ionospheric residuals of occultation events under different ionospheric conditions are simulated and analyzed. The results show that the residual of the curved ionosphere is the main error of the atmospheric inversion parameters of the occultation at the top of the mesosphere and the stratosphere, and its magnitude is closely related to the intensity of solar activity and the azimuth of the occultation plane at the local time. Ionizing interference increases the residual error of the curved ionosphere by several times to more than 20 times. A quantitative study of the regional average daily mean angular ionospheric errors of 15 ~ 35 ~ 35 km ~ (1) at the bottom of the stratosphere, 35 ~ 50 km / m of the top of the stratosphere, 50 ~ 65 ~ 65 km / m of the bottom of the middle layer and 65 ~ 65 ~ 80 km / m of the top of the middle layer has been carried out. Using MSIS90 atmospheric model and 3D NeUoG ionospheric model as atmospheric background, the occultation events of July 15, 2008 were simulated using GPS/MetOp-A real orbit data. During the analysis of the residual errors in the curved ionosphere, the world is divided into six statistical regions, GLO hemisphere high latitudea hemisphere middle latitudee hemisphere middle equalateral day time GLO day middle latitudee and SHH south hemisphere high latitude). The influence of solar activity intensity, local spherical symmetry of latitude zone and ionosphere on the residual of curved angle ionosphere is analyzed. The results show that the mean deviation of the curved ionosphere is a negative systematic deviation and increases with the increase of the solar activity intensity. In the six statistical regions, the deviation of the curved angle ionosphere is the largest, and the mean deviation of the curved angle ionosphere at the top of the middle layer, the bottom of the middle layer and the top of the stratosphere can reach 0.048 渭 radr 0.041 渭 rad and 0.032 渭 radsh, respectively, and the mean deviation of the curved angle ionosphere is the smallest. Its size is almost zero. The quantitative study on the residual errors of the curved angle ionosphere has certain reference value for the modeling and correction of the residual errors of the curved angle ionosphere in the middle and upper atmosphere. The mechanism of the ionospheric residuals in the curved angle is simulated and analyzed by means of three-dimensional ray tracing method, and the anomalous phenomena of the ionospheric residuals in the Indian Ocean region are preliminarily analyzed. The results show that the asymmetry of the electron density distribution between the "in ray" and "out ray" is the main cause of the error anomaly of the curved angle ionosphere.
【学位授予单位】：中国矿业大学
【学位级别】：博士
【学位授予年份】：2013
【分类号】：P228.4;P412

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