基于多元参照光谱的SAM岩性划分方法

光谱角制图（SAM）是一种光谱匹配方法,通过量化目标地物光谱与已知参照光谱的相似程度来判断目标地物的类型,广泛应用于多光谱遥感岩性识别。目前,岩石单元训练区内像元的均值光谱,往往作为代表该岩石单元的参照光谱来进行光谱角制图,而使用均值光谱作为参照光谱库的方法,并未考虑岩石单元内部固有的光谱差异性,很大程度上影响了SAM分类效果。为了消除SAM岩性划分时岩石单元内部的光谱差异的影响,本文采用了一种多元参照光谱的SAM岩性划分方法。首先,依据研究区已有地质资料和Landsat-8影像特征,选定各类岩石单元训练区;接着进行各岩石单元训练区内部像元的光谱差异性分析,和各训练区之间的样本可分离性分析,分别使用均值参照光谱库的SAM方法和多元参照光谱库的SAM方法对研究区Landsat-8影像进行了岩性划分实验。研究结果表明,多元参照光谱库的SAM岩性分类方法很好地改善了岩石单元内部光谱差异性对均值参照光谱库的SAM岩性分类方法的影响,分类精度显著提高。     

剪切波分裂分析系统SAM(2007)——区域地震台网资料应用实例

通过对云南、辽宁、福建遥测地震台网的波形资料分析实例,介绍了"剪切波分裂系统分析方法"软件SAM(2007)的用法。通过对区域台网资料的处理分析,表明SAM(2007)是研究剪切波分裂的一个比较实用的软件,能够有效的处理快、慢剪切波识别的问题,研究地壳介质的地震各向异性问题,能普遍用于分析国内区域地震台网资料。     

磁电法基本原理、发展现状及前景展望

磁电法作为一类特点明显的电磁勘探方法在外国(美国、加拿大、澳大利亚等)已经有了成熟的应用,但是该类方法在我国应用研究较少,甚至不为众人所知。本文从数据采集与分析、正反演技术以及应用现状3个方面详细介绍了国内外磁电法的技术原理和发展现状;总结了磁电法的优缺点及适用的条件,对于我国未来磁电法的发展提出了建议。综述表明:1)目前地面数据采集为中梯方式,可以借鉴其他应用成熟的电磁法观测方式;2)磁电法从静电场理论出发无法得到绝对电导率,可以尝试频率域理论;3)地面数据的深度分辨能力需要提高,可以通过多源多分量三维反演来提高反演的准确性;4)建议在国内将磁电法的应用范围扩展到井中、海洋以及环境和工程领域。     

ETM+(TM)蚀变遥感异常提取方法研究与应用--方法选择和技术流程

从原理、模型试验及实际数据处理等方面分析对比了比值法、光谱角法及主分量分析法的优劣;选择了以主分量分析为主、光谱角法为辅进行蚀变遥感异常的提取;引用了误差理论某些基本概念,以标准离差σ作为遥感异常切割的尺度;建立了“去干扰异常主分量门限化技术流程”。以西藏驱龙一甲马蚀变遥感异常群为例,展示了此技术的效果,并与高光谱研究结果进行了比较。     

基于光谱角匹配预测的高光谱图像无损压缩

在地表信息获取方面，高光谱遥感是对地观测技术的主要方法，观测同时产生了海量高光谱图像的存贮与传输问题.研究发现，高光谱图像具有独特的光谱上下文特征，可从光谱维分析高光谱图像的光谱相关性，并用光谱角来度量相邻像素间的光谱相似性的差异，探测水平或垂直光谱边界，由此提出了基于光谱角匹配预测(SAMP)的无损压缩算法.实验表明，SAMP算法的预测效果好于已有文献中提出的一些优秀算法，且具有低复杂性.     

Discrimination of Different Erosion Levels of Porphyry Cu Deposits using ASTER Image Processing in Eastern Iran: a Case Study in the Maherabad, Shadan, and Chah Shaljami Areas

The Lut block, eastern Iran, is one of the most extensive Cenozoic magmatic rocks, that show suitable targets for porphyry Cu-Au and high-sulfidation epithermal Au related to porphyry Cu-Au mineralization. In this study, Advanced Spaceborne Thermal Emission and Reflection Radiometer （ASTER） was used to identify different erosion levels of three porphyry Cu deposits, including Maherabad, Shadan, and Chah Shaljami, located in the Lut block volcanic-plutonic belt. Alteration minerals, including kaolinite, dickite, alunite, jarosite, epidote, chlorite, montmorillonite, muscovite, biotite, orthoclase, gypsum, and quartz, are selected to map different alteration zones and erosion levels. Distributions of end-members are mapped by using the SAM and MTMF in VNIR and SWIR of ASTER bands and the results are evaluated against the field studies. For some end-members, the results of SAM processing are more reliable compared to the MTMF because the latter looses field spectra. The use of angle threshold in the SAM, and MF-score and infeasibility value in the MTMF or low abundance of some end-members, and finally comparison of output images of spectral processing show good correlation with alteration maps. Differentiation and explanation of various erosion levels of porphyry Cu deposits are done successfully by using the ASTER sensor data.     

Streamflow variability and its relationship with climate indices in western rivers of Argentina

The objective of this study was to examine the streamflow variability of Argentinean Andean basins (22°–52°S). Trends and step changes of seven hydrological variables were analysed. In addition, relationships between the hydrological variables and Pacific Decadal Oscillation (PDO), Niño 3.4, and Southern Annular Mode (SAM) indices were analysed. Most streamflow variables showed upward trends in the northwest and central-western basins, while downward trends were identified in the Patagonia (southwestern) region. Streamflow of the central-western and Patagonian basins was positively correlated with the Niño 3.4 index. Moreover, an inverse relationship with the SAM was found in watersheds south of 37°S. Positive step changes associated with the PDO phases in the north and central-western basins in the mid-1970s were detected, while negative step changes resulted in Patagonia between 1970 and 2000. This research provides new evidence of the influence of major climate modes on streamflow variability in the western rivers of Argentina.     

地物波谱数据辅助的SPOT影像模拟真彩色方法研究

提出一种新的高分辨率遥感影像真彩色模拟方法。该方法从遥感成像光谱角度,依据地物波谱特性,采用光谱角匹配模型(SAM),首先计算出地物在绿(G)、红(R)、近红外(NIR)以及短波红外(SWIR)波段的整体和局部波谱向量角;然后根据角度距离构建最小距离隶属函数,查找对应地物波谱库中最为相似的地物波谱;最后对此条地物波谱曲线积分计算出该像素点在蓝波段的反射率。实验表明,该方法模拟出的SPOT真彩色影像在视觉效果和空间信息上优于传统的方法。