Spectro-Imaging Polarimetry of the Local Corona During Solar Eclipse     

Z. Q. Qu  G. T. Dun  L. Chang  G. Murray  X. M. Cheng  X. Y. Zhang  L. H. Deng 《Solar physics》2017,292(2):37

Results are presented from spectro-imaging polarimetry of radiation from the local solar corona during the 2013 total solar eclipse in Gabon. This polarimetric observation was performed from 516.3 nm to 532.6 nm using a prototype Fiber Arrayed Solar Optical Telescope (FASOT). A polarimetric noise level on the order of \(10^{-3}\) results from a reduced polarimetric optical switching demodulation (RPOSD) procedure for data reduction. It is revealed that the modality of fractional linear polarization profiles of the green coronal line shows a diversity, which may indicate complex mechanisms. The polarization degree can approach 3.2 % above the continuum polarization level on a scale of 1500 km, and the nonuniform spatial distribution in amplitude and polarization direction is found even within a small field of view of 7500 km. All of this implies that the coronal polarization is highly structured and complex even on a small scale.  相似文献   

电离层闪烁对GNSS的影响     

徐彬  刘钝 《全球定位系统》2011,36(3):5-8,17

电离层闪烁是影响卫星导航系统定位性能的重要因素之一。电离层闪烁可造成GNSS载噪比降低,测量误差增大,载波周跳次数增多,电离层修正精度降低,定位用精度因子变大等影响。中国南方区域是全球电离层闪烁多发区之一,电离层闪烁影响的时空范围和程度较大,是我国卫星导航应用应关注的问题。针对电离层闪烁影响,提出了我国卫星导航系统应用中可行的针对性减缓措施。  相似文献   

电离层闪烁对卫星导航系统性能影响的仿真分析     

刘钝  甄卫民  冯健  邓忠新  马宝田 《全球定位系统》2011,36(1):7-12

电离层闪烁是影响卫星导航系统定位性能的重要因素之一。通过仿真方法对中国区域用户定位性能受电离层闪烁影响的情况进行分析研究。结合电离层闪烁模型、卫星导航接收机模型和用户定位算法,仿真了中国区域内卫星导航系统用户在电离层闪烁存在情况下的定位精度性能。仿真结果表明：电离层闪烁将引起用户接收机测量误差的增大,在受电离层闪烁影响严重的中国低纬地区,用户定位误差将有明显增大,严重时可能出现定位异常。  相似文献   

An Evidence of Aerosol Indirect Effect on Stratus Clouds from the Integrated Ground-Based Measurements at the ARM Shouxian Site          下载免费PDF全文

TANG Jin-Ping  WANG Pu-Cai  DUAN Min-Zheng  CHEN Hong-Bin  XIA Xiang-Ao  LIAO Hong 《大气和海洋科学快报》2011,4(2):65-69

The aerosol effect on clouds was explored using remote sensing of aerosol and cloud data at Shouxian, China. Non-precipitation, ice-free, and overcast clouds were firstly chosen by a combination of sky images from the Total Sky Imager (TSI), cloud base heights from the Ceilometer, and vertical temperature profiles from the Balloon-Borne Sounding System (BBSS). Six cases were chosen in summer, and seven in autumn. The averaged cloud effective radii (re), cloud optical depth (COD), aerosol total light scattering coefficient (σ), and liquid water path (LWP) are, respectivey, 6.47 μm, 35.4, 595.9 mm-1, 0.19 mm in summer, and 6.07 μm, 96.0, 471.7 mm-1, 0.37 mm in autumn. The correlation coefficient between re and σ was found to change from negative to positive value as LWP increases.  相似文献   

火山活动的周期性及其在若干气候要素中的反映   总被引：1，自引：0，他引：1       下载免费PDF全文

曲维政  黄菲  杜凌  赵进平  秦婷  曹勇 《地球物理学报》2011,54(3):643-655

根据六百多年全球VEI 5级以上火山活动资料分析和谱分析以及与北半球地面气温、西太平洋高压SLP、北大西洋高压SLP和北大西洋西风漂流区SSTA对比分析得知:(1)全球强火山活动存在显著的88年左右和100年左右世纪尺度周期循环,二者对于VEI(i)原序列方差贡献率达到21.64%.还存在33年左右年代际尺度周期循环以...  相似文献   

湖北地区上地幔各向异性及其动力学意义   总被引：1，自引：1，他引：0       下载免费PDF全文

张丽芬  姚运生  廖武林  李井冈  王秋良  王墩 《地球物理学报》2011,54(1):35-43

SKS波分裂测量是研究大陆地幔的形变特征、探索大陆动力学和演化过程的重要工具.本文选用湖北数字地震台网(HB台网)和中国数字化宽频带地震台网(CB台网)提供的三分量宽频带数字化地震资料,使用旋转相关法和切向能量最小法,计算得到了湖北地区20个地震台站下方上地幔各向异性参数.结果表明,快波偏振方向较为复杂:大别造山带内,...  相似文献   

Rapid report of the 8 January 2022 MS6.9 Menyuan earthquake,Qinghai, China     

Hongfeng Yang  Dun Wang  Rumeng Guo  Mengyu Xie  Yang Zang  Yue Wang  Qiang Yao  Chuang Cheng  Yanru An  Yingying Zhang 《中国地震研究》2022,(1):4-14

The MS 6.9 Menyuan earthquake in Qinghai Province, west China is the largest earthquake by far in 2022. The earthquake occurs in a tectonically active region, w...  相似文献   

冻土静力学室内试验研究进展   总被引：1，自引：1，他引：0  

雷乐乐  谢艳丽  王大雁  陈敦  靳潇 《冰川冻土》2018,40(4):802-811

冻土力学是冻土工程学的理论基础,以解决冻土工程问题为归宿。冻土力学分为冻土静力学和冻土动力学两个方面,而冻土静力学是冻土力学的重要部分。为此,对常规冻土静力学室内试验的研究进展进行了总结,系统地阐述了其在冻土的强度特性、变形特性及理论模型等方面所取得的重要研究成果,并指出研究中存在的一些不足之处。最后结合冻土静力学研究的特点及实际冻土工程建设的需要,对冻土静力学研究的未来发展进行了展望。  相似文献   

Variation of Hg content in low sulfur coals in relation to the coal-forming environment: a case study from Zhuji Coal Mine,Huainan Coalfield,North China     

Xudong Wang  Dun Wu  Guijian Liu  Ruoyu Sun 《Environmental Earth Sciences》2018,77(19):703

Twenty-nine low sulfur coal samples were selected to determine the magnitude and variability of mercury (Hg) content in a well-documented stratigraphy system including ten continuous coal seams in Zhuji Coal Mine, Huainan Coalfield, Anhui Province, North China. Mercury content of samples was measured on a direct mercury analyzer and confident results were obtained as evaluated by standard references, sample replicates and procedural blanks. The calculated overall mine average Hg content is 71.19?±?9.28 ng/g based on seam averages and weighting by the estimated reserve of each coal seam. The estimated Hg emission potential for Huainan coalfield is obviously lower than that calculated from coal emission factor in industrial use. An increasing trend of Hg content with the evolution of depositional environment was observed from Nos. 3 to 11-2 coal seams. Combining the evidence of sedimentology and paleontology, a better understanding was gained of the mechanism of Hg sequestration in specific coal benches. A large portion of Hg residing in the low sulfur coals presumably integrated to the functional groups of organic constitution, whereas pyrite was generally abundant in the high sulfur coals.  相似文献   

电离层扰动对局域增强系统的影响分析     

龚羽霞  刘钝 《全球定位系统》2015,(2):67-71,80

卫星导航局域增强系统采用差分技术实现高精度定位能力。电离层扰动现象将对局域增强系统产生严重影响。电离层暴降低了电离层延迟空间相关性,进而影响差分定位的精度;电离层闪烁引起卫星信号质量和测量质量的降低,同时伴随闪烁产生的电离层电子密度不均匀体也会降低电离层延迟的空间相关性,影响差分定位精度。电离层扰动对局域增强系统的影响应通过接收机设计、增强系统设计、完好性实现方法等多方面的改进加以应对。  相似文献