Refinement of lunar TiO2 analysis with multispectral features of Chang’E-1 IIM data     

Xianmin Wang  Peimin Zhu 《Astrophysics and Space Science》2013,343(1):33-44

We develop a method based on the samples from Apollo and Luna landing sites to determine lunar TiO₂ content with Chang’E-1 interference imaging spectrometer (IIM) imagery. By analyzing the nonlinear relationship between the optical and compositional parameters of lunar soil samples, the method employs two Support Vector Machines (SVMs) to estimate the titanium abundance of the lunar surface. Developed with the soil compositions of the Apollo and Luna sample-return stations, the RMS (root mean square) error of our method is 0.24 wt% TiO₂, and the correlation coefficient of the TiO₂ values and our predicted ones is 99.72 %. Compared with the other 3 models, the method proposed in this paper exhibits a good performance for determining the chemical composition of the lunar surface. TiO₂ maps of Sinus Iridum, part of the Marius Hills plateau, and part of Mare Smythii are produced using our method, which could be useful for future lunar missions.  相似文献   

缝洞型储层模型AVO属性特征分析     

王丽萍  顾汉明  李宗杰 《地质科技情报》2013,(3):197-201

塔里木盆地是我国最大的含油气盆地,拥有巨大的油气资源潜力。但塔中地区奥陶系岩溶缝洞型储层埋藏深、类型复杂、储层非均质性强,所表现出的岩石地球物理特性不清楚。为了分析典型缝洞型储层模型含不同流体情形下的AVO特征,建立了过玉北1井的缝洞型储层地震地质模型,模型的3个储层段对应的孔隙度分别为10%,6%和8%,分别对应Ⅰ类储层、Ⅲ类储层和Ⅱ类储层,设计了3个储层段都充填气和3个储层段分别充填气、油、水3种不同流体时的2个模型,基于正演模拟共成像点道集记录(CMP),提取截距、梯度、纵横波反射系数及流体因子,采用AVO属性交汇分析方法,寻找油气识别的最佳属性组合,为叠前反演解释提供理论基础。  相似文献   

音频大地电磁法在地下水质评价中的应用     

高敬语  谭嘉言  朱占升  张强  林昌洪 《物探与化探》2013,(5):895-898

以西北某区的地下水勘查为例,对音频大地电磁法的野外工作方法技术作了较详细的介绍,并对其应用效果进行分析。音频大地电磁法因其装备相对轻便,勘探深度相对较大,应用效果良好,在地下水勘查中有着广泛的应用前景。  相似文献   

Present-Day Vertical Motions of Tibet: Long-Term Tectonics,Short-Term Hydrology, And Other Causes?     

Jeff FREYMUELLER  WANG Qi  YANG Shaomin 《《地质学报》英文版》2013,87(Z1):32-32

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海洋TEM中心回线装置一维正演及全时域视电阻率计算   总被引：1，自引：0，他引：1  

胡俊华  昌彦君  雷胜兰  孙卫斌 《物探与化探》2013,(6):1137-1140

首先对海洋中深海区中心回线装置的瞬变电磁响应进行了一维正演计算,频率域垂直磁场分量表达式中的汉克尔积分变换采用了124点滤波系数进行数值计算;时—频域转换使用了适应时间范围较宽的余弦变换算法;然后采用连分式算法求取了典型地电模型全时域视电阻率随深度变化的曲线。结果表明,曲线基本可以反映地下电性介质的相对大小变化;并且,根据极值点可以大致确定低阻或高阻层顶界面深度。这为海洋TEM实测资料的快速定性解释以及反演初始模型参数的选定打下了基础。  相似文献   

Dipping-interface Mapping Using Mode-separated Rayleigh Waves     

Yinhe Luo  Jianghai Xia  Yixian Xu  Chong Zeng  Richard D. Miller  Qingsheng Liu 《Pure and Applied Geophysics》2009,166(3):353-374

Multichannel analysis of surface waves (MASW) method is a non-invasive geophysical technique that uses the dispersive characteristic of Rayleigh waves to estimate a vertical shear (S)-wave velocity profile. A pseudo-2D S-wave velocity section is constructed by aligning 1D S-wave velocity profiles at the midpoint of each receiver spread that are contoured using a spatial interpolation scheme. The horizontal resolution of the section is therefore most influenced by the receiver spread length and the source interval. Based on the assumption that a dipping-layer model can be regarded as stepped flat layers, high-resolution linear Radon transform (LRT) has been proposed to image Rayleigh-wave dispersive energy and separate modes of Rayleigh waves from a multichannel record. With the mode-separation technique, therefore, a dispersion curve that possesses satisfactory accuracy can be calculated using a pair of consecutive traces within a mode-separated shot gather. In this study, using synthetic models containing a dipping layer with a slope of 5, 10, 15, 20, or 30 degrees and a real-world example, we assess the ability of using high-resolution LRT to image and separate fundamental-mode Rayleigh waves from raw surface-wave data and accuracy of dispersion curves generated by a pair of consecutive traces within a mode-separated shot gather. Results of synthetic and real-world examples demonstrate that a dipping interface with a slope smaller than 15 degrees can be successfully mapped by separated fundamental waves using high-resolution LRT.  相似文献   

地面核磁共振找水反演   总被引：10，自引：4，他引：6       下载免费PDF全文

戴苗  胡祥云  吴海波  蒋龙聪  杨迪琨 《地球物理学报》2009,52(10):2676-2682

简要介绍了地面核磁共振找水的正演理论方法,采用高斯求积并结合连分式展开的方法对核磁共振核函数中包含双重贝塞尔函数的积分核进行了数值积分,进而计算出精度较高的核函数值,在此基础之上,讨论了导电性对地面核磁共振信号的影响.基于奇异值分解算法,对核磁共振找水理论模型进行了反演研究,在不导电的情况下,重构出了比较理想的含水率分布.总结并改进了模拟退火算法,用改进的模拟退火算法分别对覆盖层高阻和导电条件下的核磁共振人工合成数据进行了反演,试验结果表明,利用改进的模拟退火算法反演地面核磁共振是可行的,而且反演结果较稳定,收敛速度较快.  相似文献   

Ionospheric response to the geomagnetic storm on 13–17 April 2006 in the West Pacific region     

Biqiang Zhao  Weixing Wan  Libo Liu  K. Igarashi  K. Yumoto  Baiqi Ning 《Journal of Atmospheric and Solar》2009,71(1):88-100

This paper presents an investigation of geomagnetic storm effects in the equatorial and middle-low latitude F-region in the West Pacific sector during the intense geomagnetic storm on 13–17 April, 2006. The event, preceded by a minor storm, started at 2130 UT on April 13 while interplanetary magnetic field (IMF) B_z component was ready to turn southward. From 14–17 the ionosphere was characterized by a large scale enhancement in critical frequency, foF2 (4～6 MHz) and total electron content (TEC) (～30TECU, 1TECU=1×10¹⁶el/m²) followed by a long-duration negative phase observed through the simultaneous ionospheric sounding measurements from 14 stations and GPS network along the meridian 120°E. A periodic wave structure, known as traveling ionospheric disturbances (TIDs) was observed in the morning sector during the initial phase of the storm which should be associated with the impulsive magnetospheric energy injection to the auroral. In the afternoon and nighttime, the positive phase should be caused by the combination of equatorward winds and disturbed electric fields verified through the equatorial F-layer peak height variation and modeled upward drift of Fejer and Scherliess [1997. Empirical models of storm time equatorial electric fields. Journal of Geophysical Research 102, 24,047–24,056]. It is shown that the large positive storm effect was more pronounced in the Southern Hemisphere during the morning-noon sector on April 15 and negative phase reached to lower magnetic latitudes in the Northern Hemisphere which may be related to the asymmetry of the thermospheric condition during the storm.  相似文献   

A numerical solution for non-Darcian flow to a well in a confined aquifer using the power law function     

Zhang Wen  Guanhua Huang  Hongbin Zhan 《Journal of Hydrology》2009,364(1-2):99-106

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Modelled and observed anomalies of tidal gravity factors     

《Physics and Chemistry of the Earth, Part A: Solid Earth and Geodesy》2000,25(4):395-399

Direct modelling of the tidal δ-factors anomalies has been carried out for M₂ and O₁ waves using the approach of S.Molodenski (1979). Resulting lateral anomalies of δ-factors are less than 0.1 % and are similar to the anomalies of high quality tidal gravity data selected from ICET Data Bank, although the latter ones are one order larger in magnitude. The correlation of tide gravity anomalies with heat flow (Melchior hypothesis) is considered for best continental stations and no correlation is found.  相似文献