Mapping shoreline indicators on a sandy beach with supervised edge detection of soil moisture differences     

《International Journal of Applied Earth Observation and Geoinformation》2019

This study describes a method to map shoreline indicators on a sandy beach. The hypothesis is that, on this beach, spectral albedo is predominantly determined by moisture content and water lines can, therefore, be detected as albedo contrasts. A laboratory experiment is performed to relate moisture content to image albedo, and supervised edge detection is subsequently used to map the shoreline indicators with remote sensing imagery. The algorithm is tested with data from visible, near-infrared and shortwave-infrared wavelength regions. These results are compared to shoreline indicators obtained by a field survey and a shoreline indicator derived from a digital elevation model. Both the water line present when the imagery was acquired, as well as the maximum extent of the last flood, can be detected as a single edge. Older high water lines are confused with the last high water line and appear dispersed, as there are multiple debris lines present on the beach. The low water line, usually in saturated sand, also appears dispersed due to the presence of channels and troughs. Shorelines are constant moving boundaries, which is why shoreline indicators are used as a proxy. Unlike a mathematical indicator that is based on an elevation model, our method is more sensitive to the dynamic nature of shorelines. Supervised edge-detection is a technique for generating reproducible measurements of shoreline indicator positions over time, and aids in the monitoring of coastline migration.  相似文献   

中国特别重大自然灾害损失统计的最新进展——《特别重大自然灾害损失统计制度》解析     

周洪建  王丹丹  袁艺  郝明月 《地球科学进展》2015,30(5):530-538

以《特别重大自然灾害损失统计制度》(简称《统计制度》)主要执笔人的视角,详细阐述了制度的主要内容、蕴含的科学问题和未来研究方向。《统计制度》报表和指标设计在与现有国家标准保持一致、历经汶川地震等多次重特大灾害实践检验完善、充分吸收相关行业部门意见和建议、适用于多灾种与灾害链损失统计、实用于灾后恢复重建规划编制等方面均体现出其权威性与最新性,《统计制度》具备科学性、综合性、实用性和动态性等特征。《统计制度》在推进特别重大自然灾害损失综合评估、启发涉灾行业部门开展专项深入研究、引领地方建立相关制度等方面具有极大潜力。  相似文献   

A review of indicator minerals and sample processing methods for geochemical exploration     

Malcolm Gent  Mario MenendezJavier Toraño  Susana Torno 《Journal of Geochemical Exploration》2011

Geochemical exploration based on the analysis of indicator minerals (IMs) is becoming increasingly used as an effective method for mineral exploration for many types of mineral deposits. The types of IMs used or recommended for exploration for different types of deposits, their properties suitable for concentrating them, as well as those of other common minerals from which they must be separated are listed.  相似文献   

广西那坡盆地火山岩-碳酸盐岩混杂型滑塌堆积:特殊的弧前域构造指相标志及其大地构造意义   总被引：1，自引：1，他引：0  

夏磊  闫全人  向忠金  夏文静  时上钧  江文  李晓剑  卫巍 《岩石学报》2018,34(3):685-700

本文详细调查揭示,位于中越边境地区的那坡弧前盆地北部边缘发育17处滑塌堆积,有些表现为火山岩-碳酸盐岩块混杂型滑塌堆积,即由火山岩滑塌块体和碳酸盐岩滑塌块体无序堆积而成;有些只是具软沉积变形特征的薄层碳酸盐岩滑塌块体;还有些是砂屑灰岩滑塌块体与碳酸盐岩(或钙质)浊积岩组合以及单一的碳酸盐岩浊积岩或碳酸盐岩碎屑流。碳酸盐岩质块体流和碎屑流一般夹于大型或巨型滑塌块体间,而碳酸盐岩(或钙质)浊积岩和块状砂岩等一般发育于滑塌堆积的远端,有的覆盖于滑塌块体之上。无论是时代还是地球化学组成,滑塌堆积中的具枕状构造的火山岩块与盆地北侧富宁县架街一带的早-中三叠世弧火山岩完全一致。具软沉积变形特征的薄层碳酸盐滑塌岩块中发育有厚30cm左右的风暴沉积层,暗示这些滑塌岩块是发育于火山弧边缘的或其上的局部的碳酸盐岩台地(主要为潮坪-潟湖相)沉积。与全球不同造山带弧前盆地对比表明,这些滑塌堆积是一种发育于构造活动强烈的弧前盆地边缘的特殊的事件沉积,可作为识别弧前域大地构造相单元的普适性沉积标志,也可用以分析断定俯冲增生造山极性。本文对碳酸盐岩滑塌块体的原始层理和软沉积变形的滑塌褶皱轴面方位测量统计揭示火山弧斜坡大体向南西方向(232°~240°)倾斜,滑塌堆积远端浊积岩古水流测量与校正结果揭示沉积物搬运方向为南或南西向,这表明华南地块与北越地块之间的古特提斯分支洋盆在早三叠世期间是向北俯冲消化减的。  相似文献   

哈密宏源铅锌矿地质地球化学特征及找矿标志     

田吉山  马金林  齐利平  王京壮  马涛  王丹阳 《新疆地质》2013,(2)

宏源铅锌矿位于塔里木板块北缘中天山地块东段,于2003年检查1∶50000水系沉积物测量铅锌银综合异常时发现,目前规模为中型铅锌矿.在前人工作基础上,对矿床地质地球化学特征和找矿标志进行总结,为该区寻找此类型矿床提供依据及找矿标志.  相似文献   

Prediction of Salmonella in seawater by total and faecal coliforms and Enterococci     

Maria A. Efstratiou  Athena Mavridou 《Marine pollution bulletin》2009,58(2):201-205

The power of total coliforms (TC), faecal coliforms (FC) and Enterococci to predict the presence of Salmonella in seawater was investigated. Indicator cut-off values with the most satisfactory combination of sensitivity and specificity in predicting Salmonella presence were 1000 CFU 100 ml⁻¹ TC, 200 CFU 100 ml⁻¹ FC, 500 CFU 100 ml⁻¹ Enterococci. When TC or FC were used for Salmonella prediction in logistic regression, then the addition of another indicator did not have a statistically significant effect. When Enterococci were used for prediction, then the addition of either of the two other indicators led to a statistically significant improvement (P = 0.001 for TC, P = 0.003 for FC). These results suggest that using either TC or FC alone provided an adequate indicator of Salmonella presence, but a statistically significant improvement is possible over using Enterococci alone. Concerning Enterococci, European Union limits for excellent coastal water quality (100 CFU 100 ml⁻¹) and United States Environmental Protection Agency criteria for marine bathing waters (35 CFU 100 ml⁻¹) have the same value in predicting Salmonella absence (92.5%).  相似文献   

矿物——成矿与找矿     

赵振华  严爽 《岩石学报》2019,35(1):31-68

单颗粒矿物微量元素激光原位定量分析测试数据的大量积累和研究,使矿物成为矿床地球化学研究和矿床勘查的重要示踪剂。本文重点选择磁铁矿、磷灰石、石榴子石、榍石、锆石、绿泥石和绿帘石等的原位分析研究所获得的认识,介绍单颗粒矿物成分组合及变化在矿床类型划分、成矿年龄测定、氧逸度、成矿过程与物质来源、找矿与勘探等方面的应用。不同矿床类型中普遍存在的矿物,如磁铁矿、磷灰石等的微量元素含量及组合差异,提供了矿床类型识别的标志。单颗粒矿物,特别是矿石矿物和密切共生矿物如锡石、铌钽铁矿、赤铁矿、石榴子石、方解石等的原位定年,使成矿年龄的直接准确测定成为现实。矿物中变价元素,如Fe、V、Mn、Ce、Eu含量和/或比值的变化,指示了成矿过程氧逸度及其变化特点。从矿物核部向震荡环带与边部的微量元素含量或同位素组成的变化,示踪了成矿过程中流体来源或性质的变化。斑岩和矽卡岩矿床中与成矿作用关系密切的蚀变矿物,如绿泥石、绿帘石的形成温度、特征微量元素比值,如Ti/Sr、Ti/Co、V/Ni、Mg/Sr等,与距矿床中心距离呈线性函数关系,可定量预测距矿床中心的距离,使以绿泥石、绿帘石为代表的找矿指示矿物研究迅速发展。  相似文献   

用协同—指示克立格预测储层物性参数：以胜利油田罗家砂四上砾岩为例     

向晓丽  张玺 《矿物岩石》1999,19(3):65-68

指示克立格是一种非参数统计方法,它能在不舍弃特异值的条件下进行有效的空间估计,协同克立格以协同区域化变量的研究对象,充分考虑了变量空间相关性和变量间的统计相关性,有着单变量克立格法可可比拟的优点,因而,本文提出协同－指示克立格法这一方法,在指示克立格中考虑多变量的空间相关性和变量间的统计相关性,使指示克拉立格与协同克立格相互补充,模拟现实,提高预测精度,并以胜利油田罗家砂四上砾岩为例进行参数预测,  相似文献   

Assessing Uncertainty Associated with the Delineation of Geochemical Anomalies   总被引：2，自引：0，他引：2  

Costa  Joao Felipe  Koppe  Jair Carlos 《Natural Resources Research》1999,8(1):59-67

A pedogeochemical exploratory survey of gold deposits was carried out in the region of São Sepé (southernmost Brazil). The region comprises a predominantly metamorphosed belt of volcanoclastics, sediments, serpentinites, basalts, gabbros, chert, tuffs, and banded iron formation of the Proterozoic age. The anomalies were identified first by stream sediment heavy mineral survey at the regional scale of exploration. Once spatial continuity was modeled, ordinary block kriging was performed to generate geochemical maps. Indicator block kriging also was used as an alternative in analyzing and interpreting geochemical data. A novel approach is proposed, which combines both ordinary and indicator kriging for delineating geochemical anomalies. Probability maps proved to be appropriate for selecting new sites for further exploration. Gold anomalies in soils trending NE were well defined by geostatistical analysis and subsequently confirmed by drilling.  相似文献   

结合序贯指示模拟的贝叶斯高斯混合线性反演          下载免费PDF全文

印兴耀  贺东阳  宗兆云  李坤  肖张波  张仟策 《地球物理学报》2019,62(12):4805-4816

高斯混合模型(Gaussian Mixture Model, GMM)可以用来描述储层性质的多峰分布特性,多峰特性主要是由于它们在不同离散变量内的变化而引起的.在高斯混合模型中,高斯分量的权值代表离散变量的概率.然而,基于高斯混合模型的贝叶斯线性反演可能会对某些点的离散变量错误地分类,进而影响连续变量的反演结果,尤其存在强噪声的时候.在本文中,我们考虑了离散变量的空间变化性,并将高斯混合模型与序贯指示模拟(Sequential Indicator Simulation, SIS)相结合来确定离散变量的后验条件权值,形成了结合序贯指示模拟的贝叶斯高斯混合线性反演方法.该方法能够准确地对离散变量进行归类,且具有良好的抗噪性.通过模型试算,我们证明了这种方法的可行性,并在实际资料中取得了较好的结果.  相似文献