降雪及旅游活动对金佛山表层岩溶泉水化学的影响     

刘跃  贺秋芳  于正良  赵瑞一  张陶  刘宁坤 《中国岩溶》2018,37(6):819-826

金佛山是世界自然遗产,冬季到景区赏雪的游客众多。为探究降雪过程及旅游活动对金佛山表层岩溶泉的影响,本文对2014年12月一次大规模降雪前后的水房泉水化学变化进行高频自动取样监测,获取高分辨率的水化学变化曲线,与大气降水、土壤水及污水的理化特征进行比较,并采用主成分分析法剖析影响泉水化学的主要因素。结果表明泉水理化学指标在降雪的不同阶段表现出显著的动态变化:在积雪初期（2014-12-10至2014-12-14）大部分水化学指标基本稳定;此后至积雪大面积融化前（2014-12-15至2014-12-28）旅游排污量增大,泉水的水温、流量、浊度、盐度以及各项离子含量呈上升趋势,而pH、溶解氧则呈下降趋势,水化学指标变幅大;积雪融化期间,融水补给使泉水溶解氧和浊度上升,其他水化学指标先下降后上升。主成分分析显示旅游活动的污水输入是引起泉水水质变化的首要因素,主成分贡献率达59%;积雪融化的稀释作用能一定程度缓解流域地下水污染状况,是第二影响因素,贡献率31%。   相似文献   

Landslide scar/soil erodibility mapping using Landsat TM/ETM+ bands 7 and 3 Normalised Difference Index: A case study of central region of Kenya     

《Applied geography (Sevenoaks, England)》2015

Landsat series multispectral remote sensing imagery has gained increasing attention in providing solutions to environmental problems such as land degradation which exacerbate soil erosion and landslide disasters in the case of rainfall events. Multispectral data has facilitated the mapping of soils, land-cover and structural geology, all of which are factors affecting landslide occurrence. The main aim of this research was to develop a methodology to visualize and map past landslides as well as identify land degradation effects through soil erosion and land-use using remote sensing techniques in the central region of Kenya. The study area has rugged terrain and rainfall has been the main source of landslide trigger. The methodology comprised visualizing landslide scars using a False Colour Composite (FCC) and mapping soil erodibility using FCC components applying expert based classification. The components of the FCC were: the first independent component (IC1), Principal Component (PC) with most geological information, and a Normalised Difference Index (NDI) involving Landsat TM/ETM+ band 7 and 3.The FCC components formed the inputs for knowledge-based classification with the following 13 classes: runoff, extreme erosions, other erosions, landslide areas, highly erodible, stable, exposed volcanic rocks, agriculture, green forest, new forest regrowth areas, clear, turbid and salty water. Validation of the mapped landslide areas with field GPS locations of landslide affected areas showed that 66% of the points coincided well with landslide areas mapped in the year 2000. The classification maps showed landslide areas on the steep ridge faces, other erosions in agricultural areas, highly erodible zones being already weathered rocks, while runoff were mainly fluvial deposits. Thus, landuse and rainfall processes play a major role in inducing landslides in the study area.  相似文献   

PCA方法在GPS坐标时间序列分析中的应用     

郑海刚  王雪莹  李军辉 《地理空间信息》2013,11(2):117-117,121

以安徽及邻区8个GPS连续站点的观测数据为基础,应用主成分分析法提取其共模误差,并对扣除共模误差前后的残余时间序列进行了对比分析。结果显示,扣除共模误差后的残余时间序列的周期性变化较为明显,数据信噪比有所提高。  相似文献   

基于PCA结合污染物迁移模型的油气田开采影响环境的风险评估研究          下载免费PDF全文

王健宇  宋晶晶  陈蓓 《盐湖研究》2022,30(3)

为改善油气田开采过程中的环境,本文结合主成分分析法(Principal Component Analysis)与污染物迁移模型,对研究区的油气田开采过程中的污染物进行了分析,主要研究其在土壤中的迁移程度。本研究首先介绍了油气田开采产生污染物的研究背景与污染物种类,其次结合主成分分析法对污染物中的主要成分进行了筛选,最后构建污染物迁移模型,对污染物在土壤以及水体中的迁移进行了研究。结果表明,本文中的主要污染物为石油类、酸、氟离子、氯离子和COD(Chemical Oxygen Demand)、BOD(Biochemical oxygen demand),石油类所占比重最大,为23.63%;石油类污染物在黑钙土中的迁移最广,直至土层厚度为35cm,污染物浓度从18365 mg/kg降到0;石油类污染物在黑钙土中的迁移符合负指数规律;当酸液浓度在1%、2%、3%、4%时,氢离子在土壤中随深度的变化一致,土层厚度为20cm时,11%的酸液酸值高于低浓度土壤酸值,11%的酸液在快速淋滤状态下比缓慢淋滤快一步到达定值;氯离子和氟离子的迁移深度变化基本符合负指数变化规律;低浓度的污染物比高浓度的污染物更早达到定值;石油类污染物在土壤中的迁移能力较弱;本次研究实验值与模拟值基本一致,研究成果良好。石油类污染物在土壤中的迁移能力较弱,酸性污染物对土壤有一定影响。  相似文献   

Soil discrimination using diffuse reflectance Vis–NIR spectroscopy in a local toposequence     

José Francirlei Oliveira  Michel Brossard  Pedro Rodolfo Siqueira Vendrame  Stanislas Mayi III  Edemar Joaquim Corazza  Robélio Leandro Marchão  Maria de Fátima Guimarães 《Comptes Rendus Geoscience》2013,345(11-12):446-453

Vis–NIR spectroscopy is nowadays presented as a possible routine method for soil sample analysis. However, there is still no consensus on which is the best multivariate statistical method to use. We propose to use principal component analysis to complete the spectral data treatment. The soil samples came from a pedological cover made up of red–yellow Latosols: 88 samples of 11 soil profiles on four toposequences were collected; clay, organic matter, silica, iron, aluminum and titanium total contents were determined; the contents of goethite, hematite, gibbsite, and kaolinite were calculated. Diffuse reflectance Vis–NIR spectroscopy at wavelengths from 400 to 2400 nm combined with principal component analysis (PCA) was sufficiently sensitive to discriminate different Latosols. Wavelengths of 700 nm and 2200 to 2300 nm were influenced by content ratios of organic matter and iron oxides (700 nm), and kaolinite and gibbsite absorption (2200 and 2300 nm). The spectral responses were affected not only by the content of these constituents, but also by the composition of the minerals, so that the same class of Latosol may have different or similar spectral responses. The role of microaggregation is discussed.  相似文献   

西藏冈底斯地区斑岩铜矿识别的最佳多光谱遥感异常判据研究   总被引：2，自引：1，他引：1  

张玉君  曾朝铭 《矿床地质》2012,31(4):671-698

文章应用多光谱遥感技术,对冈底斯斑岩铜矿带的实例(驱龙、甲玛、朱诺、冲江、夏玛日等矿床)进行了研究和总结,包括ASTER和ETM+数据技术特征、蚀变异常找矿的地质依据、蚀变异常提取的波谱前提、多光谱矿致遥感异常提取的常见技术方法、去干扰异常主分量门限化技术流程、冈底斯斑岩铜矿带找矿模型最佳遥感异常判据研究等.确定了ASTER主分量分析提取的羟基异常OHA6、OHA5同心套合异常可做为斑岩铜矿的最佳多光谱遥感异常判据,在从夏玛日至朱诺的13景共46万平方公里的ASTER提取异常中,依此判据圈定了冈底斯20处有潜能的斑岩铜矿异常.此外,还对夏玛日景遥感异常进行了解译,并提出了3处钻孔孔位建议.  相似文献   

基于PCA和BP神经网络的径流预测     

聂敏  刘志辉  刘洋  姚俊强 《中国沙漠》2016,36(4):1144-1152

径流预测为流域水资源的合理开发利用与统筹配置提供依据。运用多元线性回归、主成分回归、BP神经网络及主成分分析和BP神经网络相结合的方法,对新疆呼图壁河流域石门水文站2009-2011年各月径流量进行预测,并采用相关系数、确定性系数及均方根误差对各模型预测精度进行比较。结果表明：（1）神经网络等智能算法具有高速寻优的能力,对短时间尺度的月径流量的预测结果较好;（2）主成分回归等常规算法能充分反映出某地区径流的年际的稳定性,对全年径流总量的模拟精度较高;（3）主成分分析和BP神经网络相结合的方法,提高了神经网络的收敛速度,同时降低了局部极值的影响,优于简单的BP神经网络,适用于呼图壁河月径流量预测。  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   

Annual and spatial variations of chemical and physical properties in the Ross Sea surface waters (Antarctica)     

Serena Massolo  Roberta Messa  Paola Rivaro  Riccardo Leardi 《Continental Shelf Research》2009

Temperature, salinity, meltwater percentage, water column stability, dissolved oxygen and nutrients were measured in seawater samples collected at three fixed depths (0, 20, 100 m) in 104 stations located in three different areas of the Ross Sea (Antarctica), during four Italian Antarctic surveys carried out between 1998 and 2006. Nutrient data were used to quantify the nutrient removal, which appears particularly high in 2006, especially in polynya area. The N:P and Si:N disappearance ratios were studied to estimate the dominant phytoplanktonic community. No significant differences in the nutrient drawdown ratio were observed, in fact the N:P ratio was always below the Redfield standard ratio.  相似文献