利用独立分量分析进行火山灰云遥感检测          下载免费PDF全文

李成范  戴羊羊  赵俊娟  尹京苑  周时强 《地震地质》2014,36(1):137-147

火山灰云不但引起全球气候和环境系统的重大变化,而且还会威胁航空安全。热红外遥感技术为检测火山灰云提供了新手段,但是遥感数据自身的冗余和波段相关性大大降低了火山灰云的检测精度。独立分量分析(Independent Component Analysis,ICA)能够实现遥感数据的去相关和消除冗余,在火山灰云检测中具有一定的潜力。通过探索火山灰云的物理、化学性质,文中以2010年4月19日冰岛艾雅法拉(Eyjafjallajokull)火山灰云MODIS图像为数据源,在对MODIS数据进行主成分分析处理的基础上,利用ICA进行火山灰云检测。结果表明:ICA能够较好地从MODIS图像中获取火山灰云信息,所得结果与美国地质调查局标准光谱数据库和火山灰云SO2浓度分布具有较好的一致性,取得了较好的检测效果。  相似文献   

基于对象变化矢量分析的土地利用变化检测方法研究     

王丽云  李艳  汪禹芹 《地球信息科学学报》2014,16(2):307-313

变化检测是资源和环境遥感应用的一个重要内容。在变化矢量分析法的基础上,本文提出采用变化矢量-主成分分析法提取研究区变化信息,首先,对不同时相的遥感影像进行差值运算得到差值影像,再对其进行主成分变换并选取主分量,最后,使用多尺度分割获取影像对象。在影像分割的基础上,采用变化矢量-主成分分析方法构建自动检测规则提取变化信息,并作精度评价。研究表明：基于对象的变化矢量-主成分分析方法不仅可克服传统的基于像元式方法难以利用空间信息的缺陷,有效避免了“椒盐”噪声,而且可将多波段差值信息经主成分变换后集中在几个累计贡献率较高的主成分分量上;同时,结合了变化矢量法与主成分分析法的优点,与单独使用变化矢量分析法相比提取精度明显提高。  相似文献   

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张昊楠  匡翠林  卢辰龙  周元华 《大地测量与地球动力学》2013,33(4):137-141

?????????????????????????С??????????????PCA???????GPS??????????????????????????????????????????????????????Ч????????·??Ч?????????????, ????λ?????  相似文献   

南洛河流域洛南盆地表土孢粉与植被的关系     

张文超  李春海  鹿化煜  田先华  张红艳  雷昉  唐领余 《地理学报》2013,68(3):398-413

选取南洛河上游洛南盆地10 种植被类型下40 处样点表土苔藓开展孢粉与植被关系的研究.结果表明,表土中孢粉组成能很好地反映植被类型.森林表土中乔木植物花粉含量平均值大于40%,且有较高含量的中华卷柏孢子;疏林草原、灌丛群落中乔木植物花粉平均含量分别为13.2%和16.6%,灌木植物花粉相对草丛群落含量较高;草丛群落和农田中乔木花粉平均含量均<10%,草本植物花粉>80%,灌木植物花粉<1%.洛南盆地表土孢粉总浓度平均为1.42×10⁵粒/g,与植被覆盖度关系较弱,而与植被类型有一定联系,能辅助植被类型的辨识.聚类分析和PCA分析都能较好区分森林和非森林植被,前者能较好地区分松林和混交林,后者能较好地区分农田和灌、草丛植被,且比聚类分析更加稳定.松属、栎属等乔木花粉具有较强的扩散能力,能指示区域植被,松属没有表现出很强的超代表性,栎属具有低代表性;蒿属花粉与植被覆盖度间的相关关系较差,具有明显的超代表性,其大量出现与人类的干扰有一定的联系,禾本科花粉具有很好的植被指示性和低代表性,藜科花粉的高含量主要指示了高强度的人类活动;中华卷柏孢子在地层中的大量出现具有指示森林或松林环境的意义.  相似文献   

Groundwater contamination with arsenic in Sherajdikhan,Bangladesh: geochemical and hydrological implications     

M. A. Halim  R. K. Majumder  S. A. Nessa  K. Oda  Y. Hiroshiro  B. B. Saha  S. M. Hassain  Sk. A. Latif  M. A. Islam  K. Jinno 《Environmental Geology》2009,58(1):73-84

An integrated study has been carried out to elucidate the distribution and occurrence of arsenic in selected groundwater samples in the area of Sherajdikhan, Bangladesh. Arsenic and other parameters (T, pH, EC, Na⁺, K⁺, Ca²⁺, Mg²⁺, Cl⁻, NO₃ ⁻, SO₄ ²⁻, HCO₃ ⁻, PO₄ ³⁻, Fe, Mn and DOC) have been measured in groundwater samples collected from shallow/deep tube wells at different depths. Hydrogeochemical data suggest that the groundwaters are generally Ca–Mg–HCO₃ and Mg–Ca–HCO₃ types with bicarbonate (HCO₃ ⁻) as the dominant anion, though the other type of water has also been observed. Dissolved arsenic in groundwater ranged from 0.006 to 0.461 mg/l, with 69% groundwater samples exceeded the Bangladesh limit for safe drinking water (0.05 mg/l). Correlation and principal component analysis have been performed to find out possible relationships among the examined parameters in groundwater. Low concentrations of NO₃ ⁻ and SO₄ ²⁻, and high concentrations of DOC, HCO₃ ⁻ and PO₄ ³⁻ indicate the reducing condition of subsurface aquifer where sediments are deposited with abundant organic matter. Distinct relationship of As with Fe and Mn, and strong correlation with DOC suggests that the biodegradation of organic matter along with reductive dissolution of Fe–Mn oxyhydroxides has being considered the dominant process to release As in the aquifers studied herein.  相似文献   

Spatial distribution of metals in ground/surface waters in the Chandrapur district (Central India) and their plausible sources   总被引：1，自引：0，他引：1  

D. R. Satapathy  P. R. Salve  Y. B. Katpatal 《Environmental Geology》2009,56(7):1323-1352

This study addresses a framework to evaluate and map environmental hazard with reference to spatial distribution of major and trace metal contamination and its relationship with lithology in Chandrapur district of Maharashtra, India using geospatial, statistical and GIS tools. In all, 208 ground water and 35 surface water samples were collected using global positioning system (GPS) synoptically with satellite imagery IRS P6 LISS III and were analyzed in ICP-AES. Analytical results reflect the presence of major and trace metals in ground water in terms of % as Fe (48%), Mn (12%), Zn (9%), Al (8%), Pb (7%), Cu (6%), Ni (4%), Cd (3%) and Cr (3%) of the total average concentration. The contamination is attributed to weathering of rocks and also to mining activities. Similarly, surface water contribution of major and trace metals was found as Al (47.8%), Fe (42.8%), Mn (5.5%), Zn (2.3%), Pb (0.56%), Ni (0.42%), Cu (0.16%), Cr (0.16%) and Cd (0.10%) of the total average concentration. Ordinary kriging interpolation method was adopted to assess the spatial distribution of different major and trace metals in groundwater samples with their best model fit variogram Classical statistical method like principal component analysis (PCA) was carried out in order to establish correlation between spatial pattern of metal contamination and geology of the area in GIS environment. Various surface and subsurface aspects like landuse/land cover, structural features, hydrogeology, topography etc were also considered to ascertain their impact to supplement the inference of the study.  相似文献   

Organochlorine pesticides in fish from the southern Baltic Sea: levels, bioaccumulation features and temporal trends during the 1995-2006 period   总被引：1，自引：0，他引：1  

Szlinder-Richert J  Barska I  Mazerski J  Usydus Z 《Marine pollution bulletin》2008,56(5):927-940

The levels of HCH isomers, HCB and summation DDTs were determined in five species of Baltic fish collected during 1995-2006. Some downward time trends of HCH isomer, pp'-DDE and pp'-DDD concentrations in Baltic fish were observed; in contrast, HCB and DDT concentrations did not exhibit any obvious trend. Concentrations of summation HCHs expressed on a lipid weight basis were very similar in all species studied. In contrast, concentrations of summation DDTs varied in tested species. The most abundant HCH isomer was beta-HCH and among DDT-related compounds, pp'-DDE prevailed. In our investigations the sampling sites were not a crucial factor for organochlorine pesticide concentrations and patterns observed in fish, but the occurrence of several inter-species differences in the bioaccumulation features of OC pesticides were observed. For cod there was a positive correlation between fish size (length) and summation DDT concentration. In herring, sprat and salmon samples, summation DDT concentrations were negatively correlated with fat content.  相似文献   

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伍吉仓  孙亚峰  刘朝功 《大地测量与地球动力学》2008,28(4):97-101

??????????GPS???????????????е???????????????????????α??????????????á??????????????PCA????Karhunen??Loeve?????KLE??????????????????GPS????????????????????з????????????÷??????????????6????????????????????GPS????????5?????????????У??????????Щ??????????д?????????????????????????????????е???????????????????????α???????????????????  相似文献   

Geochemical Characteristics and Sources of Some Chemical Components in Sediments of Zhuiiang（Pearl） River Estuary     

周怀阳彭晓彤  潘建明 《中国海洋湖沼学报》2004,22(1):34-43

Sediment cores with length of 25 - 45cm at 12 stations in Zhujiang(Pearl) River Estuary were sampled in summer of 1999. Chemical components (Al2O3 , Fe2O3, CaO, TiO2, Cu, Pb, Cr, Zn, Co, Ni, V, Ba, Sr and Y) and grain sizes were analyzed. Sediments in Zhujiang River Estuary are characterized by relatively coarse grain size. The grain sizes of the sediments in the area outside the estuary are relatively finer than those in the north part of the estuary but coarser than those in the middle of Lingdingyang and have a trend similar to the spatial distribution trend of some chemical components such as Fe2O3, Al2O3, TiO2, V, Cu, Ni, Zn and Y. This showed that grain size is an important factor that controls the spatial distribution and depth profile of chemical elements in the Zhujiang River Estuary. Frequent re-suspension, re-transportation and redistribution of settled sediment on estuary floor could be deduced from the spatial distributions and depth profiles of chemical components. Except for CaO and Sr, the chemical components always enrich at the west side of, in the middle of, and at the north side of, the estuary. Fe2O3, Al2O3, Ti, V, Cr, Ni, Zn, Cu and Y in Zhujiang River Estuary sediments mainly result from rock and soil weathering except that parts of Cr, Ni, Zn Cu and Y are anthropogenic. CaO and Sr in sediments originate from marine source. Although Co as well as Pb derives from anthropogenic sources, human activities related to Co might differ from the activities related to Pb.  相似文献   

A study on the flora of woody plants of Shanxi and the relationship among the flora of Shanxi and some regions, China     

Zhang Feng  Shangguan Tieliang 《中国地理科学(英文版)》1997,8(2):152-160

There are 463 species of woody plant, belonging to 166 genera and 70 families in Shanxi, North China. The floristic composition types of genera and species are abundant, in which the compositions distributed in temperate zones (including North Temperate, Old World Temperate and Temperate Asia), having 62 genera, are dominant and account for 38.27% in total genera (except for Cosmopolitan), and they are major constructive or dominant species of vegetation in Shanxi. The floristic compositions of woody plants of Shanxi, Hebei, Beijing, Shandong, Henan, Jiangxi and Inner Mongolia were studied comparatively by using diversity index, principal component analysis (PCA) and group-average clustering, respectively. The floristic composition of Shanxi was considerably similar to that of Hebei, Beijing and Shandong because they shared a lot of genera, specially genera distributed in temperate regions, such as Rosa, Quercus, Populus, Salix, Acer, Ulmus, Pinus etc. and their eco-environment were considerably similar. However, the flora of Shanxi was comparatively different from that of Henan, Jiangxi and Inner Mongolia by reason that there were distinct differences among their eco-geographic conditions, floristic compositions and constructive or dominant species of dominant vegetation types. Supported by Shanxi Returned Oversea Scholar Foundation, China  相似文献