基于相关系数匹配的混合像元分解算法   总被引：2，自引：0，他引：2  

杨伟  陈晋  松下文经  宫鹏  陈春晓 《遥感学报》2008,12(3):454-461

遥感影像中的混合像元不仅影响地物识别和分类的精度,而且已成为遥感科学向定量化发展的主要障碍.为此,人们已经提出了多种混合像元分解算法,其中应用最为广泛的是最小二乘法.该方法虽然具有意义明确、简单易行等特点,但也易受局部噪声、大气效应、环境辐射等因素的影响.本文将混合像元分解问题归结为一个基于光谱匹配的非线性最优化问题,并针对最小二乘法的不足提出了一种新的基于相关系数匹配(spectral correlation matching, SCM)的混合像元分解技术.通过在北京市北三环及其以北区域内案例的研究表明:在城市区域内,利用图像选取终端端元的办法,基于相关系数匹配的混合像元分解算法的总体精度高于带全约束的最小二乘法(LS)的分解结果.对比分析表明:在目标光谱的绝对值整体放大或缩小而光谱形状得到了很好的保持、及局部噪声使得光谱值显著变化但光谱形状得到了一定程度保持时,基于光谱形状的相关系数法可以得到比基于光谱绝对值的最小二乘法精度更高的分解结果.  相似文献   

广西崇左三合巨猿大洞早更新世小哺乳动物群   总被引：5，自引：0，他引：5       下载免费PDF全文

金昌柱  秦大公  潘文石  王元  张颖奇  邓成龙  郑家坚 《第四纪研究》2008,28(6):1129-1137

最近在广西崇左三合大洞发现了步氏巨猿和似人似猿共生的新层位,与之伴生的有52种小哺乳动物,占三合大洞巨猿动物群总数的62%,其中苏门答腊兔（Nesolagus）是东南亚地区首次发现的化石。小哺乳动物群以南方早更新世常见的偏皮氏毛耳飞鼠（Belomys parapearsoni）、中间猪尾鼠（Typhlomys intermedius）、拟低冠竹鼠（Rhizomys brachyrhizomyoides）、硕豪猪（Hystrix magna）、先社鼠（Niviventer preconfucianus）、拟爱氏巨鼠（Leopoldamysedwardioidesi）等为代表,根据小哺乳动物群性质和与其他动物群对比以及磁性地层年代测定,表明其时代应是早更新世中期（约距今120¹60万年前）。该动物群由树鼩、扁颅蝠、小彩蝠、飞松鼠、笔尾树鼠、猪尾鼠等几乎是旧大陆热带-亚热带森林型动物组成,缺少北方类型,基本上属于热带森林动物群,这表明了当时的自然景观为温暖湿润的热带雨林环境。三合大洞小哺乳动物群是广西地区的首次发现,对华南早更新世巨猿动物群详细划分,探讨步氏巨猿演化和早期人类环境背景等目前科学界关注的问题具有重要的意义。  相似文献   

Interaction of copper with fatty acids in Soxhlet extraction and its influence     

Ming Jin  Yanqing Xia  Tianzhu Lei  Junli Qiu  Rui Zhang 《中国地球化学学报》2008,27(2):157-160

Treatment with metallic copper for the removal of elemental sulfur from bitumen extracted from sedimentary rocks or petroleum is the most widely used method. Little attention has been paid, however, to its disadvantages. It was observed that copper can interact with some polar organic substances during conventional sulfur removal, which can strongly influence the quantitative and qualitative determination of bitumen, as has been confirmed by interaction of long-chain fatty acids with copper. The copper soap generated was analyzed by element analysis, inductively coupled plasma optical emission spectrometry （ICP-OES）, thermal analysis （TG-DSC） and Fourier Transform Infrared spectroscopy （FFIR）. Mechanism of the interaction was investigated and elucidated. Our experimental results would necessitate improvement of the present method for sulfur removal and/or a search for a new one.  相似文献   

GPS observations of the ionospheric F2-layer behavior during the 20th November 2003 geomagnetic storm over South Korea   总被引：4，自引：1，他引：3  

Shuanggen Jin  O. F. Luo  P. Park 《Journal of Geodesy》2008,82(12):883-892

The ionospheric F2-layer peak density (NmF2) and its height (hmF2) are of great influence on the shape of the ionospheric electron density profile Ne (h) and may be indicative of other physical processes within the ionosphere, especially those due to geomagnetic storms. Such parameters are often estimated using models such as the semiempirical international reference ionosphere (IRI) models or are measured using moderately priced to expensive instrumentation, such as ionosondes or incoherent scatter radars. Global positioning system (GPS) observations have become a powerful tool for mapping high-resolution ionospheric structures, which can be used to study the ionospheric response to geomagnetic storms. In this paper, we describe how 3-D ionospheric electron density profiles were produced from data of the dense permanent Korean GPS network using the tomography reconstruction technique. These profiles are verified by independent ionosonde data. The responses of GPS-derived parameters at the ionospheric F2-layer to the 20th November 2003 geomagnetic storm over South Korea are investigated. A fairly large increase in the electron density at the F2-layer peak (the NmF2) (positive storm) has been observed during this storm, which is accompanied by a significant uplift in the height of the F2 layer peak (the hmF2). This is confirmed by independent ionosonde observations. We suggest that the F2-layer peak height uplift and NmF2 increase are mainly associated with a strong eastward electric field, and are not associated with the increase of the O/N₂ ratio obtained from the GUVI instruments aboard the TIMED satellite. It is also inferred that the increase in NmF2 is not caused by the changes in neutral composition, but is related to other nonchemical effects, such as dynamical changes of vertical ion motions induced by winds and E × B drifts, tides and waves in the mesosphere/lower thermosphere region, which can be dynamically coupled upward to generate ionospheric perturbations and oscillations.  相似文献   

GIS支持的城市固体废弃物规划管理信息系统构建     

李劲  王华 《测绘工程》2008,17(1):60-63

研究了基于组件式GIS平台MapX的城市固体废弃物规划管理信息系统的设计与实现;讨论了系统框架与系统功能设计、数据库设计和系统实现的关键技术。以昆明市为例,构建了基于MapX的城市固体废弃物规划管理信息系统。该系统能够实现城市固体废弃物各类数据的采集、表达和输出,提供与城市固体废弃物管理模型无缝集成的接口,可利用地图、文字、表格等多种手段为城市固体废弃物规划管理提供辅助决策。  相似文献   

Study on Recovering the Earth＇s Potential Field Based on GOCE Gradiometry     

Wenbin Shen  Jin Li  Jiancheng Li  Zhengtao Wang  Jinsheng Ning  Dingbo Chao 《地球空间信息科学学报》2008,11(4):273-278

Given the second radial derivative Vrr（P） ｜δs of the Earth＇s gravitational potential V（P） on the surface δS corresponding to the satellite altitude, by using the fictitious compress recovery method, a fictitious regular harmonic field rrVrr（P）^＊ and a fictitious second radial gradient field V：（P） in the domain outside an inner sphere Ki can be determined, which coincides with the real field V（P） in the domain outside the Earth. Vrr^＊（P）could be further expressed as a uniformly convergent expansion series in the domain outside the inner sphere, because rrV（P）^＊ could be expressed as a uniformly convergent spherical harmonic expansion series due to its regularity and harmony in that domain. In another aspect, the fictitious field V^＊（P） defined in the domain outside the inner sphere, which coincides with the real field V（P） in the domain outside the Earth, could be also expressed as a spherical harmonic expansion series. Then, the harmonic coefficients contained in the series expressing V^＊（P） can be determined, and consequently the real field V（P） is recovered. Preliminary simulation calculations show that the second radial gradient field Vrr（P） could be recovered based only on the second radial derivative V（P）｜δs given on the satellite boundary. Concerning the final recovery of the potential field V（P） based only on the boundary value Vrr （P）｜δs, the simulation tests are still in process.  相似文献   

应用混合分布研究银川平原地下水埋深对植被的影响   总被引：1，自引：0，他引：1  

孙宪春  金晓媚  万力 《地学前缘》2008,15(5):344

银川平原地处西北干旱地区,自然生态环境在西北地区具有典型性。研究银川平原的生态环境,需要研究植被,它反映多种因素的作用。在影响植被的各种因素中,地下水对植被生长的影响非常重要,但将地下水对植被生长的影响进行定量化分离并不容易。近年来,用混合分布函数处理大量数据的方法受到越来越多的关注,但是混合分布函数的参数求解一直比较困难。文章提出了一种基于混合分布函数和数据直方图之间的关系,用最小二乘法估计参数的新方法;并用这种方法,结合银川平原遥感数据中的归一化植被指数NDVI,对地下水埋深与植被生长的关系进行定量分析,得到地下水埋深对植被影响所服从的正态分布密度函数。  相似文献   

生物气CO_2还原途径中碳同位素分馏作用研究及应用   总被引：2，自引：0，他引：2  

李谨  胡国艺  张英  杨贵芳  崔会英  曹宏明  胡须龙 《地学前缘》2008,15(5):357

地质历史中,CO2/H2还原产甲烷作用对生物气的形成具有十分重要的意义。中国柴达木盆地第四系生物气主要为CO2/H2还原型生物气。笔者以CO2/H2还原生气理论为指导,进行不同初始碳同位素值和不同赋存状态碳源的生物模拟实验,研究CO2/H2还原产气过程中发生的碳同位素分馏作用。实验结果表明,产物中δ13CH4值与底物的δ13C值呈很好的正相关关系;在反应母质过量的情况下,碳源的赋存状态可以影响产物甲烷的碳同位素组成。以游离形式CO2还原产生的甲烷δ13C值,相对于以HCO3-、CO23-离子形式产生的甲烷δ13C值轻。通过柴达木盆地东部第四系生物气田实例分析,探讨了该区生物气的主要底物CO2的来源及赋存状态,对评价盆地生物气资源和有利勘探区预测有重要的参考价值。  相似文献   

山西保德—静乐地区新近纪地层时代讨论     

朱大岗  孟宪刚  邵兆刚  雷伟志  王津  韩建恩  余佳  吕荣平  王艳 《地质通报》2008,27(4):510-516

通过对山西保德-静乐地区新近纪地层的野外地质调查和实测剖面,对分布于该区的新近纪地层进行了详细的研究和划分,获得了新的ESR和古地磁测年数据,并结合生物地层序列确定了该区新近系地层的顺序为：新近系上新统静乐组（N2j）、新近系中新统上部保德组（N1^26）和中新统下部芦子沟组（N1^1l）。  相似文献   

遥感技术在煤炭资源开发状况监督管理中的应用研究   总被引：1，自引：0，他引：1  

康高峰  卢中正李社 金谋顺 《中国煤炭地质》2008,20(1):13-16

利用高分辨率遥感图象可以快速查明煤炭资源开发状况以及煤炭资源开发的合法性（界内开采、界外开采、越界开采）等,对煤矿安全生产及维护矿业秩序具有重要意义。以我国中部某煤炭开采密集区为试验区,选择不同分辨率的遥感数据,从矿山铺助设施、道路、矿堆、矸石的特征出发,进行矿山开采状况遥感解译;以地理信息系统技术（GIS）为支撑实现采矿权数据、规划数据图层与遥感专题数据的叠加分析和相关分析,判断非法与越界矿山,评价矿产资源开发与保护规划执行情况。  相似文献