采空区二维超声波物理模型实验研究     

赵家福  田钢  石战结  王者江 《吉林大学学报(地球科学版)》2005,(Z1)

由于对资源矿产的过度开采使得矿山地区(尤其是煤矿)出现了采空区,从而引起地表塌陷等地质灾害。为了深入了解地震方法在采空区调查中的应用效果,从超声波物理模型实验研究出发,论述了物理模型的原理和制作,研究了采空区的地震波场特征,并利用W inse is软件对所采集的二维超声波实验数据进行了处理。由叠偏剖面推断的采空区的位置与实际模型相符,从而验证了超声波采空区物理模型试验是有效的、可信的;同时可以为实际探测采空区提供进一步的理论依据。  相似文献   

甘肃华亭地区铀矿化信息遥感提取方法     

张曰静  祝民强刘艳 车健仁 《华东地质学院学报》2005,28(3):230-233

从分析ETM各波段图像的信息特征入手,在黄土覆盖等环境因素干扰严重的地区,利用遥感技术对其铀矿化的信息进行了提取.在ERDAS软件的支持下,应用图像融合、波段比值、主成分分析、光谱指数等技术方法,对ETM遥感影像数据进行增强处理.其中,图像融合与传统的图像融合略有不同,是在进行图像融合前将原始图像（ETM1～5,7）进行低通滤波处理,使得融合后的图像既保留高分辨率数据的空间信息,又保留低分辨率数据的光谱信息.在对研究区的遥感数据进行增强处理后,选取有利波段组合,圈定了有利铀成矿的远景区.  相似文献   

Profondeur d'extraction racinaire et signature isotopique de l'eau prélevée par les racines des couverts végétaux     

Zakaria Boujamlaoui  Thierry Bariac  Philippe Biron  Laurent Canale  Patricia Richard 《Comptes Rendus Geoscience》2005,337(6):589-598

We seek to identify the depth to which water is extracted by the roots in the soil. Indeed, in an isotopic steady-state condition of leaf water, transpiration introduces into the atmosphere a vapour whose isotopic signature is identical to that of root water. In the isotopic models of atmospheric general circulation, it is classically allowed that the signature of transpiration belongs to the meteoric water line. This supposes that the water taken by the roots has escaped with the evaporation of the soil and comes thus from the deep layers of the soil. At the time of experimentation carried out on maize plants (Nemours, Seine-et-Marne, France), this extraction depth was inferred from the comparison between the signature of the water measured on the level of the first internode of the stems of the plants and the isotopic profile of water in the soil. When the flow of transpiration reaches a maximum value, the plant uptakes water resulting from precipitations and which preserves its non-evaporating character after having quickly infiltrated in the deep layers of the soil. This relates to only 55% of the flux transpired by the canopy, the remainder presenting an evaporating character more or less marked according to ambient conditions. This experiment invalidates the classical hypothesis used in isotopic models of general atmospheric circulation in temperate regions. In fact, only half the amount of water vapour transpired by the canopy during the day presents a signature similar to that of the rainwater sampled in deep soil layers. To cite this article: Z. Boujamlaoui et al., C. R. Geoscience 337 (2005).  相似文献   

贵州省六盘水市石漠化遥感-GIS评价     

张红玉  李武福  郭颖 《云南地理环境研究》2005,17(5):15-19

以六盘水市为研究区，以ETM遥感数据和1：25万的国家标准基础地理数据为主要数据源，辅助以地面样地调查数据，建立石漠化与诸因子相关关系模型，将诸因子转化为遥感定量指标，研究遥感专题信启，快速提取，形成RS、GIS集成的石漠化信息提取技术。通过以上技术处理，实现了六盘水市喀斯特地区的石漠化现状遥感—GIS快速调查评价，得到六盘水市石漠化信息地理数据库等数据，为政府部门实现宏观决策提供理论依据和科学数据。  相似文献   

利用主成分分析法提取绿洲水体专题信息的研究   总被引：4，自引：2，他引：4  

丁建丽 《云南地理环境研究》2005,17(2):11-14

水资源对于以荒漠为背景的绿洲具有极其重要的作用,及时掌握绿洲水体的动态变化定量信息,对于合理调控绿洲区域生态环境,可持续发展区域经济活动具有重要意义。针对塔里木盆地南部特有的极端干旱地区,选择策勒绿洲为重点研究靶区,采用主成分分析方法,提取1990和1998年两幅卫星图像中水体专题信息。与以往方法相比,该方法不仅可有效避免常规分类法中存在的误差累积,结果出现较多伪变化信息的缺陷;亦可减小辐射差异对光谱比较法的极大限制,从而直接获得水体变化信息,实现过程简单、清楚,可操作性强。  相似文献   

Bound and mobile soil water isotope ratios are affected by soil texture and mineralogy,whereas extraction method influences their measurement     

Rachel E. Adams  Ayumi Hyodo  Toby SantaMaria  Cynthia L. Wright  Thomas W. Boutton  Jason B. West 《水文研究》2020,34(4):991-1003

Questions persist about interpreting isotope ratios of bound and mobile soil water pools, particularly relative to clay content and extraction conditions. Interactions between pools and resulting extracted water isotope composition are presumably related to soil texture, yet few studies have manipulated the bound pool to understand its influence on soil water processes. Using a series of drying and spiking experiments, we effectively labelled bound and mobile water pools in soils with varying clay content. Soils were first vacuum dried to remove residual water, which was then replaced with heavy isotope-enriched water prior to oven drying and spiking with heavy isotope-depleted water. Water was extracted via centrifugation or cryogenic vacuum distillation (at four temperatures) and analysed for oxygen and hydrogen isotope ratios via isotope ratio mass spectrometry. Water from centrifuged samples fell along a mixing line between the two added waters but was more enriched in heavy isotopes than the depleted label, demonstrating that despite oven drying, a residual pool remains and mixes with the mobile water. Soils with higher clay + silt content appeared to have a larger bound pool. Water from vacuum distillation samples have a significant temperature effect, with high temperature extractions yielding progressively more heavy isotope-enriched values, suggesting that Rayleigh fractionation occurred at low temperatures in the vacuum line. By distinctly labelling bound and mobile soil water pools, we detected interactions between the two that were dependent on soil texture. Although neither extraction method appeared to completely extract the combined bound and mobile (total water) pool, centrifugation and high temperature cryogenic vacuum distillations were comparable for both δ²H and δ¹⁸O of soil water isotope ratios.  相似文献   

基于决策树分类的大屯矿区地物信息提取及矿区污染分析     

于海若  燕琴  董春  战丽丽 《测绘与空间地理信息》2016,(4):67-69,72

本文在对国内外遥感图像分类方法充分研究分析的基础上,选择决策树分类法对大屯矿区的Landsat 8遥感图像进行分类研究。选取样本提取并分析研究区典型地类光谱特征曲线,依据光谱曲线特征和归一化植被指数建立了土地利用分类决策树模型,通过反复试验和修正,筛选出适宜大屯矿区地物分类的决策树最优阈值,对研究区进行分类和精度评价,最后通过分类结果对研究区的水体污染状况进行简要分析。  相似文献   

运用ENVI实现SPOT-5卫星影像的RVI提取     

尹芬  丁美青 《测绘与空间地理信息》2016,(1)

运用ENVI软件处理长沙地区的SPOT-5影像,将全色影像和多波段影像进行融合,分析融合后的影像,再选择感兴趣区域进行影像裁剪;采用ENVI的波段运算(Band3/Band2)提取该地区比值植被指数并进行分析。结果表明:比值植被指数对植被覆盖率较高的区域有非常高的敏感度;在植被覆盖率小于50%的时候,其敏感度明显降低,在绿色植被覆盖区域的比值植被指数远大于1,在裸露地表、建筑物、水体等没有植被覆盖区域的比值植被指数则在1附近,而比值植被指数大于2的则出现在高覆盖健康绿色植被上。  相似文献   

基于光谱角匹配算法的水体信息提取研究     

齐庆超  张小磊  金江峰  金玉玲 《测绘与空间地理信息》2016,(2):93-96

针对水体信息提取时,传统算法不能较好地解决山体阴影被误提为水体的问题,引入多用于高光谱数据处理的光谱角匹配算法,以Land-sat8 OLI(band1-band7)为数据源,以黄河小浪底水库周边区域为实验区,开展水体信息提取研究,结果显示:水体指数法和波段关系提取的结果中有大量的山体阴影信息,提取精度不超过30%,而光谱角匹配法提取结果受阴影的影响较小,提取精度在99%以上。  相似文献   

地理国情普查时点核准作业方法探讨     

赵永亮  高明  张佳彬 《测绘与空间地理信息》2016,(2)

通过核实从数据采集到标准时点阶段发生变化的内容,补充新增内容,消除普查前阶段由于资料时效性和外业局限性等导致的现势性不统一现象,对变化的地理国情信息进行核准,使地理国情普查数据成果在时间上达到统一,是开展地理国情监测的基础。  相似文献