Irregular structures of the F layer at high latitudes during ionospheric heating     

E. D. Tereshchenko  M. O. Kozlova  O. V. Evstafiev  B. Z. Khudukon  T. Nygrén  M. Rietveld  A. Brekke 《Annales Geophysicae》2000,18(9):1197-1209

Results on heating the ionospheric F region above Tromsø, Norway are presented. The ionosphere was monitored by satellite tomography and amplitude scintillation methods as well as the EISCAT incoherent scatter radar. No effect of heating was observed in the daytime. In the evening and in the pre-midnight sector, noticeable tilts of the F region were observed during heating periods. The tilts overlapped the heating cone, where the electron density decreased and irregularities exceeding 10 km in size appeared. Between the heating periods the F layer was restored to its horizontal shape. The anisotropic parameters of small-scale irregularities with scale lengths of hundreds of metres were also determined. It was found that the perpendicular anisotropy points in the direction of F region plasma flow. In some cases the results can be explained by assuming that the small-scale irregularities were generated within the heating cone and drifted out of the heating region where they were subsequently observed.  相似文献   

Comparison of the orientation of small-scale electron density irregularities and F region plasma flow direction     

E. D. Tereshchenko  B. Z. Khudukon  M. O. Kozlova  O. V. Evstafiev  T. Nygrén  M. T. Rietveld  A. Brekke 《Annales Geophysicae》2000,18(8):918-926

Results are shown from an experimental campaign where satellite scintillation was observed at three sites at high latitudes and, simultaneously, the F region plasma flow was measured by the nearby EISCAT incoherent scatter radar. The anisotropy parameters of field-aligned irregularities are determined from amplitude scintillation using a method based on the variance of the relative logarithmic amplitude. The orientation of the anisotropy in a plane perpendicular to the geomagnetic field is compared with the direction of F region plasma flow. The results indicate that in most cases a good agreement between the two directions is obtained.  相似文献   

Geomagnetic control of the foF2 long-term trends     

A. V. Mikhailov  D. Marin 《Annales Geophysicae》2000,18(6):653-665

Further development of the method proposed by Danilov and Mikhailov is presented. The method is applied to reveal the foF2 long-term trends on 30 Northern Hemisphere ionosonde stations. Most of them show significant foF2 trends. A pronounced dependence of trend magnitude on geomagnetic (invariant) latitude is confirmed. Periods of negative/positive foF2 trends corresponding to the periods of long-term increasing/decreasing geomagnetic activity are revealed for the first time. Pronounced diurnal variations of the foF2 trend magnitude are found. Strong positive foF2 trends in the post-midnight-early-morning LT sector and strong negative trends during daytime hours are found on the sub-auroral stations for the period with increasing geomagnetic activity. On the contrary middle and lower latitude stations demonstrate negative trends in the early-morning LT sector and small negative or positive trends during daytime hours for the same period. All the morphological features revealed of the foF2 trends may be explained in the framework of contemporary F2-region storm mechanisms. This newly proposed F2-layer geomagnetic storm concept casts serious doubts on the hypothesis relating the F2-layer parameter long-term trends to the thermosphere cooling due to the greenhouse effect.  相似文献   

Structures of the Bohai Petroliferous Area, Bohai Bay Basin   总被引：3，自引：0，他引：3  

CAI Dongsheng  LUO Yuhui  YAO Changhu  Research Institute of the Bohai Corporation of CNOOC  Tianjin HE Jiankun  HU Shengbiao  Institute of Geology  Geophysics  Chinese Academy of Sciences  Beijing LU Huafu  WANG Liangshu Department of Earth Sciences  Nanjing University  Nanjing  Jiangsu 《《地质学报》英文版》2000,74(3):641-650

This paper, for the first time, deals with a more systematic study of the structures in the Bohaipetroliferous area that covers nearly one third of the Bohai Bay basin. The study mainly involves the effects of preexisting basement faults on the basin formation, the characteristics of basin geometry and kinetics, the modelling of the tectonic-thermal history, the polycyclicity and heterogeneity in the structural evolution and the natural seismic tomographic images of the crust and upper mantle. The authors analyze the features of the dynamic evolution of the basin in the paper and point out that the basin in the Bohai petroliferous area is an extensional pull-apart basin.  相似文献   

A comparative study of ionospheric TEC derived from DPS-4 and GPS observations at Zhongshan Station,Antarctic          下载免费PDF全文

Yu Houfang  Chen Xiangcai  Liu Jianjun  He Fang 《极地研究》1988,31(3):291

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基于极光光谱图像的氧辐射特征仿真推演     

孔婉秋  吴家骥  胡泽骏  GwanggilJeon 《南京气象学院学报》2018,10(1):113-122

极光分光光谱仪成像所得重要辐射特征包括氧原子所激发的557.7、630.0、636.4 nm谱线,这些谱线和入射电离层的高能电子能通量、中高层大气粒子成分密度等都有着紧密联系.本文结合引发极光的电子碰撞反应物理机制构建氧辐射特征仿真模型,利用极光光谱图像557.7、630.0 nm谱线估计最接近真实成像情况下的入射电子能通量,实验结果表明仿真中基于假设光强比推演得到的氧辐射谱线像素预测值较真实值高估了1~1.29倍.  相似文献   

基于北斗GEO卫星的磁暴期间电离层TEC响应分析     

白晓涛  蔡昌盛 《大地测量与地球动力学》2020,40(2):129-133

基于亚太地区北斗GEO卫星数据对2017-05发生在中低纬度地区的磁暴现象进行研究,并使用北斗GEO卫星获取的TEC实测数据对全球电离层图的精度进行评估。进一步对磁暴引起的全球电离层TEC变化进行分析发现,电离层TEC对磁暴的响应出现在磁暴主相开始1~4 h之后,最大扰动值达到20 TECu以上。  相似文献   

山区三维静校正方法研究   总被引：1，自引：0，他引：1  

郎玉泉  ;程怡  ;惠俊刚 《中国煤炭地质》2008,(6):36-39

依托国家重大产业技术开发专项“西部煤炭资源高精度三维地震勘探技术”,对“山西国阳新能股份有限公司二矿390水平九采区高精度三维地震勘探”及山西阳泉五矿首采区老资料研究二个项目进行资料处理,以攻克影响勘探精度和分辨率的静校正问题。通过对二区块地震资料分别采用绿山折射静校正、综合折射静校正、层析静校正,发现综合折射静校正相对于绿山折射静校正,可以较好的解决静校正的短波长分量、长波长分量问题,更加准确的刻化出地质构造情况,而层析静校正能够更好地解决近地表横向速度变化大、地表没有同一稳定折射层、地表存在高速体等复杂地形的静校正问题,保证同相叠加和正确成像,提高资料的分辨率及勘探精度。  相似文献   

BDS网络RTK参考站三频整周模糊度解算方法   总被引：1，自引：1，他引：0  

高猛  徐爱功  祝会忠  葛茂荣  杨秋实 《测绘学报》2017,46(4):442-452

北斗卫星导航系统是目前唯一一个全星座提供三频观测数据的卫星导航定位系统,三频观测值有助于载波相位整周模糊度的快速、准确固定。本文提出了一种BDS网络RTK参考站三频整周模糊度解算方法。首先利用B2、B3频率的观测值及严格的模糊度固定标准确定超宽巷整周模糊度,将固定的超宽巷整周模糊度与其他宽巷整周模糊度的线性关系作为约束条件,然后估计宽巷整周模糊度、相对天顶对流层延迟误差和电离层延迟误差,并搜索确定宽巷整周模糊度。利用固定的宽巷整周模糊度与三频载波相位整周模糊度的整数线性关系,将线性关系加入载波相位整周模糊度参数估计观测模型中,然后确定载波相位整周模糊度。使用实测的CORS网BDS三频观测数据进行算法验证,结果表明,该方法可正确有效地实现参考站间三频载波相位整周模糊度的快速解算。  相似文献   

顾及大气延迟误差的中长基线RTK算法     

袁宏超  秘金钟  张洪文  徐彦田  陈振 《测绘科学》2017,42(1)

针对常规RTK作业距离一般不超过15km的问题,提出了一种顾及大气延迟误差的中长基线RTK的算法,突破了常规RTK作业距离。在中长基线情况下,与大气延迟有关的误差如电离层延迟误差、对流层延迟误差等,随着基线长度的增加,空间相关性大大降低,进而影响整周模糊度的快速解算。基于卡尔曼滤波算法,采用非组合差分定位模型,对于电离层延迟误差采用了电离层加权模型进行估计,对于对流层延迟分别采用了相对对流层延迟参数估计和绝对天顶对流层参数估计。最终通过实测数据对该算法进行了算法验证和结果分析。试验结果表明:该算法可以实现中长基线RTK的快速解算,并且在估计相对对流层延迟时,绝对天顶对流层参数估计不利于基准站和流动站的对流层延迟分离,一般采用估计流动站上的相对对流层延迟。  相似文献