基于GPS技术研究南极电离层在磁暴下的响应特征

发布时间：2017-12-28 02:04

本文关键词：基于GPS技术研究南极电离层在磁暴下的响应特征　出处：《武汉大学》2017年硕士论文　论文类型：学位论文

【摘要】：电离层与磁层、中高层大气存在耦合关系,是连接近地空间和日地空间的纽带,与人类的空间活动密切相关,因此研究电离层具有非常重要的科学意义。电离层会导致无线电信号质量下降、导航与定位精度降低、天基雷达系统成像质量变差等,同时电离层在重大自然灾害(如台风、海啸、地震、火山喷发等)的孕育、发生、消散过程表现出一定的异常性,因此电离层研究还具有非常重要的应用价值。极区电离层与磁层、行星际空间直接相连,物理形态和机理与中低纬地区存在差异,在空间物理学的相关研究中具有重要地位。极区电离层的变化非常复杂,多种电离层过程和多个空间现象经常同时发生,这些变化可以直接或间接影响中低纬地区的电离层,甚至日地空间环境,因此极区电离层的研究对全球电离层也具有非常高的参考价值。由于太阳活动等因素引起的磁暴会导致电离层的异常扰动,对通讯系统、空间飞行器、导航定位精度等造成严重影响。磁暴对电离层的扰动在不同地理位置、地方时、季节会出现不同的扰动形态,同时受到磁暴等级的影响。磁暴对电离层扰动的某些规律特性及物理机制仍没有完全解决,通过分析极区磁暴对电离层响应特征,可以更深入探究磁层与电离层之间的耦合关系。本文在采用球冠谐函数对南极电离层建模的基础上,对磁暴期间的电离层响应进行了简要的分析。本文系统的研究了利用GPS技术研究南极电离层TEC的方法,在收集IGS(International GNSS Service)、POLENET(The Polar Earth Observing Network)和 CACSM(Chinese Antarctic Center of Surveying and Mapping)的 GPS 数据基础上,采用球冠谐分析理论对南极电离层TEC进行提取,分析了时空分布特征,并对磁暴期间的电离层响应进行了简要分析。主要研究内容包括:1、根据国内外研究现状介绍了电离层探测及研究的现状和发展,介绍基于GPS技术进行电离层反演的原理和方法。分析了高精度电离层TEC的计算中周跳的探测和修复、粗差的剔除、硬件延迟的解算等工作。主要介绍球冠谐分析理论建立南极电离层TEC模型的方法。2、采用球冠谐函数模型对太阳活动低年2009年和太阳活动高年2012年的数据进行建模分析。球冠谐函数的基函数在区域内具有正交性,球冠谐函数的系数的零阶项C0,0可以反映区域内的电离层TEC值的平均含量,对比球冠谐函数的零阶项系数与实测TEC日均值发现二者具有很强的相关性,相关系数达到了 0.97以上,验证了球冠谐模型参数具有的物理意义,并对其频谱特性进行了分析。探讨了南极地区整体和局部地理位置电离层TEC季节变化、周日变化,在西南极地区发现了明显的威德尔海异常现象,对其表现特征进行了简要的概括。3、通过球冠谐函数模型对2012年10月地磁暴期间电离层的响应特征进行了分析,地磁暴期间电离层日均值与地磁指数有显著的正相关,尤其在两次磁暴发生时刻,TEC值均出现了明显的下降,表明此次电离层暴为负相暴。采用球冠谐分析模型计算并绘制了全南极地区每隔2小时的电离层VTEC分布,分析表明,在全南极范围内,随着时间的推进,TEC值在08:00 UT之后进一步下降,日侧和夜侧均出现下降,在纬度较高的区域TEC下降更为明显,说明此次电离层负相暴在全南极区域出现。
[Abstract]:The ionosphere is coupled with the magnetosphere and the upper and middle atmosphere. It is the link between the near earth space and the solar terrestrial space, and is closely related to the human spatial activity. Therefore, the study of the ionosphere is of great scientific significance. The ionospheric radio signal will lead to decline in quality and decrease the precision of navigation and positioning, space-based radar system imaging quality is poor, and the ionosphere in major natural disasters (such as typhoon, tsunami, earthquake and volcano eruption etc.) the occurrence and dissipation process showed some abnormal, so also is very valuable for ionospheric research important. The polar ionosphere is directly connected to the magnetosphere and interplanetary space. The physical form and mechanism are different from those in the low and middle latitudes, which play an important role in the research of space physics. Changes in the polar ionosphere is very complex, a variety of ionospheric processes and multiple spatial phenomena often occur at the same time, these changes can be in middle and low latitude ionosphere directly or indirectly, even on the space environment, so the study of the polar ionosphere has very high reference value to the global ionosphere. The magnetic storms caused by solar activity and other factors will cause the abnormal disturbance of the ionosphere, which will seriously affect the communication system, spacecraft, navigation and positioning accuracy. The disturbances of the ionosphere in the magnetic storm are different in different geographical locations, in the place of the earth and in the season, and are influenced by the grade of magnetic storm. The characteristics and physical mechanism of ionospheric disturbances have not yet been completely solved. By analyzing the characteristics of the ionospheric response of polar geomagnetic storms, we can further explore the coupling relationship between the magnetosphere and the ionosphere. Based on the function of spherical cap harmonic modeling of Antarctic ionosphere, ionospheric response to geomagnetic storms were analyzed briefly. This paper studies the method of using GPS technology in the collection of Antarctic ionosphere TEC, IGS (International GNSS Service), POLENET (The Polar Earth Observing Network) and CACSM (Chinese Antarctic Center of Surveying and Mapping) based on GPS data, using spherical harmonic analysis theory on the extraction of Antarctic ionosphere TEC, analyzes the time and space distribution characteristics and ionospheric response to geomagnetic storms is analyzed. The main research contents include: 1. According to the research status at home and abroad, we introduce the current situation and development of ionospheric detection and research, and introduce the theory and method of ionospheric inversion based on GPS technology. The detection and repair of the cycle jump, the removal of the gross error and the calculation of the hardware delay are analyzed in the calculation of the high precision ionospheric TEC. Mainly introduces the spherical cap harmonic analysis theory to establish the TEC model of Antarctic ionosphere. 2, using the data of spherical cap harmonic function model to the low solar activity and high solar activity in 2012 2009 modelinganalysis. Basis functions are orthogonal spherical harmonic function in the region, the zero order C0,0 coefficients of spherical cap harmonic function can reflect the average content of ionospheric TEC region value, compared with the spherical cap harmonic functions of zero order coefficients with the measured TEC daily mean that the two has a strong correlation, the correlation coefficient reached more than 0.97 and verify the physical meaning of parameters with the spherical cap harmonic model, and the spectral characteristics were analyzed. The seasonal and Sunday variations of the ionospheric TEC in the Antarctic region were discussed. The obvious Weddell Sea anomaly in the southwest pole area was found, and its characteristics were briefly summarized. 3, the response characteristics of the spherical cap harmonic function model of ionospheric storms during 2012 10 month were analyzed, there is a significant positive correlation between the ionosphere during geomagnetic storms on average with the geomagnetic index, especially in two geomagnetic storms, TEC values were decreased significantly, suggesting that the ionospheric storm is a negative phase of violence. The spherical cap harmonic analysis calculation and mapping of the entire Antarctic ionosphere every VTEC distribution, 2 hours in the whole model analysis showed that the Antarctic range, with the advance of time, TEC further decreased in 08:00 after UT, day side and night side decreased, in the high latitude region of TEC decreased more significantly, indicating the ionospheric negative phase in the whole area of the Antarctic storm.
【学位授予单位】：武汉大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：P228.4;P352

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