A sub-pixel analysis of urbanization effect on land surface temperature and its interplay with impervious surface and vegetation coverage in Indianapolis,United States     

Qihao Weng  Dengsheng Lu 《International Journal of Applied Earth Observation and Geoinformation》2008

This study developed an analytical procedure based upon a spectral unmixing model for characterizing and quantifying urban landscape changes in Indianapolis, Indiana, the United States, and for examining the environmental impact of such changes on land surface temperatures (LST). Three dates of Landsat TM/ETM+ images, acquired in 1991, 1995, and 2000, respectively, were utilized to document the historical morphological changes in impervious surface and vegetation coverage and to analyze the relationship between these changes and those occurred in LST. Three fraction endmembers, i.e., impervious surface, green vegetation, and shade, were derived with an unconstrained least-squares solution. A hybrid classification procedure, which combined maximum-likelihood and decision-tree algorithms, was developed to classify the fraction images into land use and land cover classes. Correlation analyses were conducted to investigate the changing relationships of LST with impervious surface and vegetation coverage. Results indicate that multi-temporal fraction images were effective for quantifying the dynamics of urban morphology and for deriving a reliable measurement of environmental variables such as vegetation abundance and impervious surface coverage. Urbanization created an evolved inverse relationship between impervious and vegetation coverage, and brought about new LST patterns because of LST's correlations with both impervious and vegetation coverage. Further researches should be directed to refine spectral mixture modeling by stratification, and by the use of multiple endmembers and hyperspectral imagery.  相似文献   

鄂尔多斯地块早白垩世构造-热事件:杭锦旗玄武岩的Ar-Ar年代学证据   总被引：8，自引：3，他引：5  

邹和平  张珂  李刚 《大地构造与成矿学》2008,32(3)

在鄂尔多斯地块北部杭锦旗黑石头沟,于下白垩统砂岩之上发现了一层玄武岩。其SiO2(46.93%)较低而碱含量(K2O+Na2O=6.21%)较高,组合指数σ=8.0,含标准矿物Ne,属于碱性橄榄玄武岩。Ar-Ar激光阶段加热定年结果表明,该玄武岩具有126.2±0.4Ma的Ar-Ar年龄。年龄数据表明杭锦旗黑石头沟玄武岩形成于早白垩世,反映鄂尔多斯地块在早白垩世发生了一次构造-岩浆-热事件,这与华北、乃至整个中国东部在早白垩世发生了较普遍的构造-岩浆-热事件具有一致性。这次构造-岩浆-热事件可能引起深部流体自地下深部上涌及在地块内部运移,为各种成矿元素的迁移、沉淀、富集和成矿创造了合适条件。  相似文献   

福鼎山后尖玄武岩筒地质特征及其形成机制探讨     

戴清忠  陈荣魁 《福建地质》2008,27(4):369-376

福鼎山后尖玄武岩位于福鼎一福清北东向断裂带北东段,呈岩筒状产于石帽山群下组下段火山沉积岩中,属钠质碱性玄武岩系列,由玄武质火山角砾岩、碧玄岩、橄榄辉长一玄武岩组合,经历火山爆发、喷溢、次火山侵入3个阶段而形成。  相似文献   

基于模糊神经网络的模糊空间对象生成方法研究     

张辉  杨俊涛  李参海 《测绘与空间地理信息》2008,31(1):1-3

随着对GIS中的空间对象模型和自然地理特征表达的研究深入,模糊空间对象被提出。针对模糊空间对象表达的特点,提出了一种基于模糊神经网络的模糊空间对象生成方法。该方法将模糊技术与神经网络相结合,利用神经网络的学习能力调整模糊隶属函数和模糊规则,使系统具备自适应的特性。实验表明,这种基于模糊神经网络的生成模糊空间对象的方法比传统方法大大的提高了成果的精度。  相似文献   

云南个旧拉丁尼克期玄武岩地球化学特征及其大地构造背景   总被引：3，自引：1，他引：2  

黎应书  秦德先  邹滔  贾福聚  万朝英  孙彩霞  周年胜 《吉林大学学报(地球科学版)》2008,38(4)

个旧地区拉丁尼克期火山岩的地质、地球化学特征研究表明:该期玄武岩的岩石类型为杏仁状斑状纤闪石化玄武岩,属于硅不饱和、富碱、高钛,镁、铁偏高,铝偏低,具有大陆碱性橄榄玄武岩的组分特征.该玄武岩为陆内拉张环境下基性程度高、分异程度低的幔源岩浆分异的产物,形成于大陆板内裂谷环境,并与拉裂作用有关.  相似文献   

重要找矿指示元素的野外快速分析法——金的野外快速分析     

卢荫庥  王晓苓 《物探与化探》1993,17(6):449-455

近年来,作者发展了七种以上重要找矿指示元素的野外快速分析法,此乃其一。文中提出一种新的金样冷浸技术,引进了新的光导光度检测方法,样品经溴化钠—硫酸—过氧化氢冷浸,用经丙酮—MIBK处理的泡沫塑料富集金,经混合解脱剂解脱并直接取解脱液用改进的微珠析出法或用光导光度法测定。取10g样品,可测定0.0005-50g/t范围内的金。方法简便、快速,可在普查分队驻地进行,每一工作日可测定80多个样品,由于废弃了王水分解样品和泡沫塑料的灰化,具有广阔的应用前景。  相似文献   

珠穆朗玛峰高程与板块构造运动问题     

杨志强  王文颖 《地球科学与环境学报》1993,(4)

喜马拉雅山是由印度板块和欧亚板块相碰撞而形成,这已被当代多数有关科学家所认识。一些测量数据也表明喜马拉雅山现在仍在快速隆升。而喜马拉雅山主峰——珠穆朗玛峰的高程的测定,也成为当代地学界的热点。本文结合最新资料对精确测定珠峰高程的一些问题,诸如水准基面、峰顶标志和积雪等进行了讨论。  相似文献   

南海北部陆缘新生代玄武岩地球化学特征及成因     

曹楚奇  熊发挥  杨胜标  徐向珍  刘飞  牛晓露  冯光英  邱添  杨经绥 《地质学报》2022,96(8):2683-2704

南海盆地及周缘地区新生代玄武岩对揭示南海盆地的演化历史至关重要，然而这些玄武岩的成因还存在争议。本文研究了位于南海北部陆缘的海南岛临高县多文组玄武岩岩石地球化学和矿物地球化学特征，并探讨其成因和构造背景。多文组玄武岩主要由橄榄石、单斜辉石、斜长石、斜方辉石、铬尖晶石和铁钛氧化物等组成。橄榄石Fo值变化于55. 5~71. 1之间，Ni的含量较低， Fe/Mn比值较高。铬尖晶石Cr#值为74. 1~82. 7，Mg#值为45. 5~63. 8， Ti的含量较高。斜方辉石Mg#值为63. 9~79. 6，单斜辉石为66. 0~80. 6。单斜辉石稀土配分曲线富集MREE，亏损LREE和HREE，呈拱形分布。斜长石以中- 拉长石为主(Ab36. 56~52. 78), 富集LREE、Ba、Sr和Eu。铁钛氧化物的TiO2含量为50. 19%~51. 46%。多文组玄武岩原始岩浆的主量和微量元素组成与夏威夷、峨眉山、塔里木等玄武岩组成一致，地幔源区包含了辉石岩的成分，而且其地幔潜在温度(＞1400℃)和氧逸度(ΔNNO)要高于大洋中脊玄武岩(N- MORB)，表明多文组玄武岩的形成与海南地幔柱活动有关。由于海南地幔柱形成时代明显晚于南海盆地的扩张时代，认为南海地幔柱是南海盆地伸展的被动响应。  相似文献   

Geochemistry and Origin of Ananai Stratiform Manganese Deposit in the Northern Chichibu Belt, Central Shikoku, Japan     

Koichiro Fujinaga    Tatsuo Nozaki  Takazumi Nishiuchi  Kiyoko Kuwahara  Asuhiro Kato 《Resource Geology》2006,56(4):399-414

Abstract. Major and trace element contents are reported for Permian manganese ore and associated greenstone from the Ananai manganese deposit in the Northern Chichibu Belt, central Shikoku, Japan. The manganese deposit occurs between greenstone and red chert, or among red chert beds. Chemical compositions of manganese ore are characterized by enrichments in Mn, Ca, P, Co, Ni, Zn, Sr and Ba, and negative Ce and positive Eu anomalies relative to post-Archean average Australian Shale (PAAS). Geochemical features of the manganese ore are similar to those of modern submarine hydrother-mal manganese deposits from volcanic arc or hotspot setting. In addition, geochemical characteristics of the greenstone closely associated with the Ananai manganese deposit are analogous to those of with-in plate alkaline basalt (WPA). Consequently, the Ananai manganese deposit was most likely formed by hydrothermal activity related to hotspot volcanism in the Panthalassa Ocean during the Middle Permian. This is the first report documenting the terrestrially-exposed manganese deposit that was a submarine precipitate at hotspot.  相似文献   

快速城市化过程中城市土地覆被的时空动态特征     

龚建周  夏北成 《福建地理》2006,(4)

1990~2005年间,是广州市经济快速发展和城市景观变化最大的时期,以同时段TM影像解译得到广州市的土地覆被类型图,从数量结构、空间信息及位置转移和景观等方面,分析了广州市土地覆被的动态特征.数量结构的研究结果显示:在快速城市化过程中广州市的耕地、林地等自然资源的利用程度在加大,自1995年起,这种变化的趋势开始减缓;土地覆被类型之间的信息与位置的转移变化频繁,并且表现出空间位置分异的特征.景观特征指数分析结果表明:广州市城市土地覆被向破碎化方向发展,城市建设用地呈扩展之势.  相似文献