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基于地球化学背景的多图幅系统误差校正——以区域地球化学调查数据Au元素为例 总被引：1，自引：0，他引：1
针对区域地球化学图件中出现的含量等值线环绕子区边界现象,以Au的多个图幅拼接为例,使用了分幅标准化法、衬度返回法及定和化法3种方法对地质大调查以来新方法获得的某成矿带区域地球化学数据进行系统误差校正,校正后编制地球化学等量线图显示,所采用的3种校正方法对于研究区数据存在的系统误差都不能达到较好的调平效果。针对研究区数据特点,尝试在分幅标准化法和衬度返回法基础上提出基于地球化学背景的误差校正方法,进一步对4种方法校正后数据参数特征及编制地球化学等量线图进行对比。基于地球化学背景的误差校正方法对研究区达到了较好的数据校正效果,并对校正前后数据进行相关对比和检验,满足化探数据中存在的系统误差属于线性误差这一基本假设,在实际应用中,可供地球化学数据系统误差校正灵活地使用,以取得更好的应用效果。 相似文献
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均匀性检验是环境标准样品研制的重要技术环节,在均匀性检验过程中,数据漂移对环境标准样品均匀性判定及其不确定度评定的影响不容忽视。本文结合实例,从实验方案和数理统计方法等方面探讨了随机分析法、随机区组法、内插校正法、趋势分析校正法等均匀性检验实验方案及数据漂移校正方法。提出采用t检验法判断数据漂移的显著性,在数据漂移趋势不显著的情况下,采用随机分析法进行标准样品的均匀性检验。在数据漂移显著的情况下,宜采用内插校正法或趋势分析校正法对均匀性数据进行漂移校正。以某土壤中Ni元素均匀性检验为例,经采用内插校正法和趋势分析校正法校正漂移数据后,测量值的相对标准偏差(RSD)由3.0%分别下降为1.4%和1.2%,直线模型斜率的绝对值由0.2003 mg/kg分别下降为0.02870mg/kg和4.709×10~(-5)mg/kg。土壤中Ni、Cu、Co、Tl等4种重金属元素的瓶间均匀性不确定度分量(u_(bb))与随机分析法相比,下降最高达78%。在长时间分析测试过程中数据漂移校正效果欠佳的情况下,宜采用随机区组法进行标准样品的均匀性检验。 相似文献
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激光法粒度筛析校正研究 总被引：1，自引：0，他引：1
激光法和筛析法分析作为两种最常见的用于沉积地质粒度分析的方法,其间的数据转换校正是在数据对比、数据对接时经常遇到且无法回避的问题。为此设计了两个实验,实验一对比了窄粒度范围样品两种分析方法的分析结果,统计分析了筛析法比激光法偏大的幅度,并提出一个校正方法;实验二对不同磨圆程度的样品进行分析,研究了磨圆度与两种分析方法差异程度之间的相关关系,认为实验一提出的校正方法适合一般条件下的天然沉积物粒度分析校正。文章又以实例展示了所提出的校正方法的校正效果并讨论了激光粒度法存在的问题。激光粒度分析法用于天然沉积物粒度分析时,结果常见明显的光滑化、正态化、双峰合并现象,扭曲了真实的粒度分布。文章认为实际样品具体情况远远复杂于米氏理论的设定条件,样品条件参数并未全部带入计算过程,所以激光法粒度求解是不精确的。更好的数据校正方法有待于激光粒度仪的软件、硬件改进。激光法合理的用于天然沉积物粒度分析还有一些问题需要讨论。 相似文献
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含量—面积法是基于分形理论,一种研究含量与曲面面积之间关系的方法.这里以云南省个旧西区某地Sn元素土壤化探数据为例,利用MAPGIS平台进行化探数据处理,研究其含量与面积的关系,并确定异常下限,圈定异常范围.同时与传统方法进行对比分析,结果表明,基于分形含量—面积法圈定的异常区域更加有效、合理. 相似文献
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黑河流域天然植被的面积变化研究 总被引：8，自引：1，他引：8
植被覆盖面积的大小是反映区域性生态环境状况的重要指标之一,多年植被覆盖面积的变化则直观反映了植被生态环境随时间的变化规律。在前人研究成果的基础上,采用定量遥感技术,应用美国国家航天航空局最新的全球植被指数变化研究数据(GIMMS)作为数据源,对黑河流域1989-2002年间的植被面积变化规律进行了研究。考虑到实际的植被面积难以确定,因此采用等效面积法确定植被覆盖面积,通过统计遥感图像上植被指数(NDVI)值大于0.3的像素点值,以像素点值代表植被的面积,研究黑河流域14 a的天然植被面积变化规律。研究结果证明,黑河流域的天然植被在以每年约3%的速度减少。 相似文献
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根据1986年和2000年的TM影像数据,利用地理信息系统(GIS)技术通过景观斑块的转移矩阵计算,分析了石羊河流域凉州区和民勤两个典型绿洲近15年来的土地利用变化;并利用不同时期中下游绿洲水资源量和开发利用程度,结合种植业结构,分析了该区域水资源利用动态变化。结果表明,耕地大量增加,凉州区和民勤绿洲分别增加了6302 hm2和36434 hm2,民勤绿洲林地大面积减少,2000年林地面积仅为1986年的55%,绿洲面积减少了23365 hm2;而中游凉州区绿洲面积却增加了8167 hm2;上下游用水量之比从20世纪50年代的1.612急剧增大到90年代的8.33,用水矛盾日益突出,下游水库来水量40年来下降达63.1%;地下水开采强度日益增加,机井分布密集,地下水位大幅度下降;种植业结构不合理,耗水量较大的粮食作物所占的比例过大。 相似文献
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黑河下游额济纳绿洲变化规律及其相关因素分析 总被引：7，自引：0，他引：7
通过处理额济纳旗地区的卫星数据,以归一化植被指数为重要指标,对可能影响绿洲的各种人为和自然因素进行了定量分析,其中包括年径流量、年降雨量、高程、坡度和地下水埋深等。结果表明:当通过狼心山的黑河流量大于3×108m3/a时,额济纳绿洲面积与黑河下游径流量呈良好的线性关系;该地区植被的生长和降雨几乎无关,两者相关系数为0·016;绿洲植被生长与高程有一定关系,最适宜绿洲植物生长的高程为930~950m;坡度和植被生长也有一定关系,坡度小的地方,植被相对茂密;地下水埋深对植被的生长存在密切的关系,用植被覆盖率的概念得到最适宜绿洲植物生长的地下水位埋深为3·2~3·8m。 相似文献
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黑河下游额济纳绿洲退化规律及其控制因素 总被引：4，自引：1，他引：4
本文针对黑河下游的额济纳绿洲，借助遥感方法利用气象卫星数据定量确定了绿洲的多年动态变化规律，通过地下水数值模拟得到地下水水位埋深分布，提出植被覆盖率的概念较好地描述了植被生长状况与地下水位埋深的定量关系，最终给出了能从宏观上研究干旱区绿洲和水资源定量关系的实用方法。 相似文献
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The changes of vegetation cover in Ejina Oasis based on water resources redistribution in Heihe River 总被引：1，自引：0，他引：1
Wang Yaobin Feng Qi Si Jianhua Su Yonghong Chang Zongqiang Xi Haiyang 《Environmental Earth Sciences》2011,64(7):1965-1973
The Ejina Oasis (EO), located in arid northwest China, is a typical arid area in the world. The ecosystem in the oasis has
become worse since the 1990s. However, it began to improve after the Chinese government took the mandatory measure to redistribute
the water in Heihe in 2000. To understand this change, the remote sensing images in 1990, 2000 and 2006 were selected, and
exertion related Land Use/Cover Change (LUCC) model was employed. Results showed that: (1) non-vegetation cover was the main
body of the vegetation cover in oasis, showing a trend of increase at the beginning and diminution later, while low, medium
and high vegetation cover was the other way around; (2) the area of low, medium and high vegetation cover in 2006 was less
than that in 1990; the status and trend index P
t of oasis vegetation cover was 0.62 in 1990–2000, which means that the oasis ecosystem of Ejina was getting worse and was
under an unbalanced status; P
t was 0.27 in 2000–2006 indicating that the oasis ecosystem was restored obviously and the whole system tended to be balanced;
(3) all of these changes should be attributed to the water resources redistribution in Heihe River, which played a leading
role, as well as the measures and relevant policies taken by the local government, which promoted the rapid recovery of the
medium and high vegetation. 相似文献
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中国西北地区额济纳绿洲植被盖度与黑河流量的滞后效应研究 总被引：6，自引：1，他引：5
干旱区植被生长与地下水的关系是生态水文地质学研究的热点之一。西北干旱地区,由于降水稀少,绿洲是当地人类生存和发展的主要依托。近年来,随着黑河流域中游地区用水量的逐年加大,下游来水量减少,使得下游额济纳绿洲的面积不断减小,湖泊干涸,沙漠化严重,生态环境恶化。由于绿洲植被的生长与水有极为密切的关系,因此,研究河流流量与绿洲植被生长之间的定量关系,对改善黑河流域生态环境、协调用水矛盾和合理配置水资源具有重要意义。将遥感数据与黑河径流量数据相结合,在区域尺度上定量研究额济纳绿洲植被生长与河流径流量的关系。结果表明,绿洲植被对黑河径流以及地下水有很强的依赖关系,而且黑河径流对额济纳绿洲的影响存在一年的滞后期,而地下水则通过这种滞后作用将两者联系起来。 相似文献
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利用SPOT VGT NDVI数据对石羊河流域1999—2010年期间植被覆盖的时空变化进行了研究,并基于像元二分模型求算植被覆盖度,以植被覆盖度为指标对研究区荒漠化程度进行定量监测与评价。结果表明:12年来石羊河流域植被覆盖度整体呈增加的趋势,增加速率为0.003 2 a-1。植被改善的面积远大于植被退化的面积,植被改善区域的面积为11 130 km2,占研究区总面积的26.45%,主要分布在金昌、永昌、民勤、武威东部以及古浪的西北部地区;植被退化区域的面积为3 546 km2,占研究区总面积的8.43%,主要分布在天祝藏族自治县的东部和古浪南部的乌鞘岭地区。荒漠化土地面积整体呈下降的趋势,极重度荒漠化土地明显减少,转化为重度荒漠化;非荒漠化土地的增加主要以绿洲的扩张为主。 相似文献
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Application of hyperspectral remote sensing for environment monitoring in mining areas 总被引：2，自引：1，他引：1
Environmental problems caused by extraction of minerals have long been a focus on environmental earth sciences. Vegetation
growing conditions are an indirect indicator of the environmental problem in mining areas. A growing number of studies in
recent years made substantial efforts to better utilize remote sensing for dynamic monitoring of vegetation growth conditions
and the environment in mining areas. In this article, airborne and satellite hypersectral remote sensing data—HyMap and Hyperion
images are used in the Mount Lyell mining area in Australia and Dexing copper mining area in China, respectively. Based on
the analyses of biogeochemical effect of dominant minerals, the vegetation spectrum and vegetation indices, two hyperspectral
indices: vegetation inferiority index (VII) and water absorption disrelated index (WDI) are employed to monitor the environment
in the mining area. Experimental results indicate that VII can effectively distinguish the stressed and unstressed vegetation
growth situation in mining areas. The sensitivity of VII to the vegetation growth condition is shown to be superior to the
traditional vegetation index—NDVI. The other index, WDI, is capable of informing whether the target vegetation is affected
by a certain mineral. It is an important index that can effectively distinguish the hematite areas that are covered with sparse
vegetation. The successful applications of VII and WDI show that hyperspectral remote sensing provides a good method to effectively
monitor and evaluate the vegetation and its ecological environment in mining areas. 相似文献
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Xianguo TUO Wunian YANG Huaiyong SHAO Zhengqi XU Keliang MU 《中国地球化学学报》2006,25(B08):37-38
Remote sensing is an effective method to monitor environmental change. To study the influence of mining and mine dump on the environment of mine, remote sensing is used to monitor the change of land use and vegetation in the ore area, and to forecast the ecological environment by considering the mining speed. Remote sensing images at different periods were collected in the study, which include MSS images in 1975, TM images in 1990, 1995, 2000 and 2005, and SPOT-5 images in 2002. At the same time, relief map and geological map of the ore area were also collected as assistant data for remote sensing interpretation. After color synthesis, enhancing treatment and geometrical revision, the interpreted dynamic information on remote sensing images was edited with ARC/INFO software, to build a dynamic monitoring database for land use in the ore area from 1975 to 2005 and a database for land use in 1975, 1990, 1995, 2000, 2002 and 2005. Through interpretation, it is found that, after 30 years of mining activities, the vegetation area in the Panzhihua mining area was reduced from 9352.6 ha in 1975 to 8195.6 ha in 2005, and its grassland area from 1053 ha in 1975 to 795.5 ha in 2002. After that, the grassland area increased to 869.1 ha in 2005 because of re-cultivation of some mine dumps. 相似文献
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在南岭高海拔山脉、植被茂密等地区开展地质调查难度大,人员和物资难以进入,因此需提前根据该区域的地形线性特征合理设计野外调查路线;此外地形线性特征可为区域构造运动信息的认知提供辅助知识.遥感技术以其宏观性、多尺度、多层次的特点成为地质研究和地质勘查的重要手段,然而在高植被覆盖区,常见的光学影像难以穿透植被,而微波雷达遥感则因为较好的植被穿透性,使得其应用成为可能.因此,提出了一种基于雷达卫星Sentinel-1和数字高程模型（digital elevation model,DEM）数据的地形线性特征提取方法.该方法首先利用似然比边缘检测算法提取Sentinel-1影像中的边缘特征,然后对DEM进行线性特征增强以生成山体阴影影像,再利用Canny边缘检测算子提取DEM数据中的山脊线与山谷线等主要线性特征,以DEM提取出的特征线为中心建立缓冲区并与雷达影像的提取结果做相交处理,将得到的线性特征利用道格拉斯-普克算法进行局部直线拟合,最后得到研究区的地形线性特征.结果表明,该方法综合考虑了雷达影像的微观细节信息和DEM数据的宏观趋势信息,在保留主要线性地形特征的同时剔除了伪边缘和噪声点,提取效果较好. 相似文献
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Quanjun Jiao Bing Zhang Liangyun Liu Zhenwang Li Yuemin Yue Yong Hu 《Natural Hazards》2014,70(2):1309-1326
The 8.0-magnitude Wenchuan earthquake in 2008 damaged the ecology of northwestern Sichuan, China. This study assessed ecological changes within a few years of the earthquake through satellite observations of vegetation dynamics in the earthquake area. As an ecological indicator, the fractional vegetation cover was extracted using the Normalized Difference Vegetation Index based on multi-year Landsat images and was validated using airborne images. We found that the entire mountainous disaster area had recovered by 68.45 % 3 years after the 2008 earthquake. After rapid recovery of vegetation in 2009, the recovery process slowed. The vegetation recovery rate (VRR) in the area heavily damaged by landslides was slightly lower but nearly that of the entire disaster area. In addition, because of differences in the proportions of soil and rock in the damaged areas, recovery of vegetation in the southwest portion of the study area was slower than in the northeast areas. Topographic analysis of vegetation recovery patterns indicated that damage to vegetation was closely related to slope, while recovery of vegetation was more sensitive to elevation. The landscape analysis showed that the recovery rate (65.21 %) of the excellent vegetation cover type was slower than the overall VRR. This study suggests that vegetation recovery is a slow ecological process and that ecological restoration should be implemented in mountainous regions affected by the earthquake. 相似文献