塌岸地质灾害遥感监测方法研究

结合遥感技术发展现状,从塌岸灾害体识别、灾害体监测、灾害影响因素监测、灾害承灾体识别与隐患分析四个方面阐述了遥感技术在塌岸地质灾害监测研究中的内容、方法及作用,提出了解决问题的思路,初步构建了塌岸地质灾害遥感监测的技术方法体系。     

Overview and modeling of mechanical and thermomechanical impact of underground coal gasification exploitation

From an economic point of view Underground Coal Gasification (UCG) is a promising technology that can be used to reach coal resources that are difficult or expensive to by conventional mining methods. Furthermore, the process addresses safety concerns, by avoiding the presence of workers underground. An optimal UCG process requires the integration of various scientific fields (chemistry, geochemistry, geomechanics) and the demonstration of limited of environmental impacts. This paper focuses on the mechanical component of the UCG operation and its impact on the surrounding environment in terms of stability and land subsidence. The mechanical components are also considered. Underground mining by coal combustion UCG challenges include the mechanical behavior of the site and of stability of the overburden rock layers. By studying the underground reactor, its inlet and outlet, we confirm the key role played by mechanical damage and thermo-mechanical phenomena are identified. Deformation or collapse above the cavity may cause a collapse in the overlying layers or subsidence at the surface level. These phenomena are highly dependent on the thermoporomechanical behavior of the rock surrounding the cavity (the host rocks). Unlike conventional methods, the UCG technology introduces an additional variable into the physical problem: the high temperatures, which evolve with time and space. In this framework, we performed numerical analyses of the coal site that could be exploited using this method. The numerical results presented in this paper are derived from models based on different assumptions describing a raw geological background. Several 3D (3 dimensional) and 2D (2 dimensional, plane) nonlinear finite element modelings are performed based on two methods. The first assumes a rock medium as a perfect thermo-elastoplastic continuum. In the second, in order to simulate large space scale crack propagation explicitly, we develop a method based upon finite element deactivation. This method is built on a finite element mesh refinement and uses Mohr-Coulomb failure criterion. Based on the analysis of the numerical results, we can highlight two main factors influencing the behavior and the mechanical stability of the overburden, and consequently the UCG process evolution. The first is the size of the cavity. This geometrical parameter, which is common to all types of coal exploitation, is best controlled using the classic exploitation method. We show that in the case of UCG, the shape of the cavity and its evolution over time can be modified considerably by the thermomechanical behavior of the host rocks. The second is the presence of a heat source whose location and intensity evolve over time. Even if thermal diffusivity of the rock is low and only a small distance from the coal reactor is thermally affected, we show that the induced mechanical changes extend significantly in the overburden, and that subsidence can therefore be estimated at the surface. We conclude the integration of the mechanical analysis into a risk analysis process mechanical analysis can be integrated in a thorough risk analysis.     

基于遥感对土地退化监测与评价的几个方法

本文结合生态学,以地面监测和遥感原理、遥感反演、建模手段浅谈土地退化监测与评价的方法。     

遥感技术在湖泊水质监测中的应用

环境污染遥感监测技术具有监测范围广、速度快、成本低,且便于进行长期的动态监测等优点,是实现宏观、快速、连续、动态地监测环境污染的有效方法,已成为湖泊环境动态变化监测的重要技术手段.湖泊水质遥感监测是基于经验、统计分析或水质参数的光谱特征,选择遥感波段数据与地面实测水质参数数据进行数学分析,建立水质参数反演模型实现的.在运用遥感技术对湖泊进行水质监测的方法中有传统方法和神经网络模型.与传统方法相比,神经网络模型有较强的水质识别的容错性,水质状况识别的可信度.今后,神经网络模型、高光谱遥感技术以及RS与GIS、GPS的结合运用等将是遥感技术在此领域中的发展方向.     

溢油事故监测中的遥感技术

溢油事故日益频繁,对溢油的监测尤为重要,文章介绍了溢油事故监测中遥感技术的运用进展,包括了航空遥感、卫星遥感以及两者在溢油事故中的联合运用。     

流域地表生态信息的卫星遥感图像处理技术

以福建省九龙江流域为例,利用计算机技术和遥感-GIS工具软件,探讨利用多源卫星遥感影像获取流域地表环境信息的图像处理与分析技术,列举卫星遥感可获取的流域地表生态环境专题信息。重点分析利用遥感-GIS界定流域范围的方法、流域地表覆盖状况和植被覆盖密度的卫星遥感影像处理方法。      

Reaction rate constants in simulation of underground coal gasification using porous medium approach

Underground coal gasification (UCG) is an emerging energy technology for a cleaner type of coal extraction method. It avoids current coal mining challenges such as drastic changes to landscapes, high machinery costs, elevated risks to personnel, and post-extraction transport. UCG has a huge potential to provide a clean coal energy source by implementing carbon capture and storage techniques as part of the process. In order to support mitigation strategies for clean coal production and policy development, much research needs to be completed. One component of this information is the need to understand what happens when the coal burns and a subsurface cavity is formed. This paper looks at the efforts to enhance reliable prediction of the size and shape of the cavities. Reactions are one of the most important mechanisms that control the rate of the growth of the cavities. Therefore, modeling the reactions and precise prediction of reaction kinetics can influence the accuracy of a UCG process. The produced syngas composition during UCG is closely linked to the reactions that take place in this process, the permeability of the coal seam, and the temperature distribution. Since the combination of reactions can influence the distributions of the heat and gas components in the coal seam during UCG or even extinguish the combustion, accurate modeling of the reactions is crucial, particularly when all phenomena affecting the reaction rate are considered in a single set of kinetics. In this study, procedures are proposed to estimate the frequency factor and activation energy of the pyrolysis reaction using a single-step decomposition method, the kinetics of the endothermic direction of homogeneous reversible reactions, and the frequency factor of heterogeneous reactions from experiments or literature data. The estimated kinetics is more appropriate for simulation of the UCG process using the porous medium approach. Computer Modelling Group’s CMG-STARS (Steam, Thermal, and Advanced Processes Reservoir Simulator) software is used in this study.     

水体污染卫星遥感监测探讨

本文主要介绍了水体污染卫星遥感监测的主要内容,着重介绍了卫星遥感技术在水体油污染、水体悬浮物浓度、水体富营养化以及城区污水等监测方面的应用,并阐述了水体污染卫星遥感监测的主要方法,以期对我国水体污染的监测及控制有所裨益。     

基于遥感和地统计分析的滑坡监测研究评述

在滑坡监测过程中,常规技术方法往往会受到气候与地形的限制,且连续观测能力较差,实施困难较大.而遥感技术可以克服观测条件的限制,并可针对滑坡不同阶段实行监测.此外,地统计分析方法可充分利用遥感数据本身具有的空间相关性,可以提高影像信息提取的准确性.因此,遥感与地统计方法集成用于滑坡监测具有广阔的应用前景.     

Mitigation and adaptation strategies for global change via the implementation of underground coal gasification

Coal is the most abundant hydrocarbon energy source in the world. It also produces a very high volume of greenhouse gases using the current production technology. It is more difficult to handle and transport than crude oil and natural gas. We face a challenge: how can we access this abundant resource and at the same time mitigate global environmental challenges, in particular, the production of carbon dioxide (CO₂)? The editors of this special edition journal consider the opportunity to increase the utilization of this globally abundant resource and recover it in an environmentally sustainable manner. Underground coal gasification (UCG) is the recovery of energy from coal by gasifying the coal underground. This  process produces a high calorific synthesis gas, which can be applied for electricity generation and/or the production of fuels and chemicals. The carbon dioxide emissions are relatively pure and the surface facilities are limited in their environmental footprint. Unused carbon is readily separated and can be geo-sequester in the resulting cavity. The cavity is also being considered as a potential option to mitigate against change impacts of other sources of carbon dioxide (CO₂) emissions. These outcomes mean there is an opportunity to provide developing and developed countries a source of low-cost clean energy. Further, the burning of coal in situ means that the traditional dangers of underground mining and extraction are reduced, a higher percentage of the coal is actually recovered and the resulting cavern creates the potential for a long-term storage solution of the gasification wastes. The process is not without challenges. Ground subsidence and groundwater pollution are two potential environmental impacts that need to be averted for this process to be acceptable. It is essential to advance the understanding of this practice and this special edition journal seeks to share the progress that scientists are making in this dynamic field. The technical challenges are being addressed by researchers around the world who work to resolve and understand how burning coal underground impacts the geology, the surface land, and ground water both in the short and the long term. This special issue reviews the process of UCG and considers the opportunities, challenges, risks, competitive analysis and synergies, commercial initiatives and a roadmap to solutions via the modelling and simulation of UCG. Building and then disseminating the fundamental knowledge of UCG will enhance policy development, best practices and processes that reflect the global desires for energy production with reduced environmental impact.     

Project Specific Monitoring and Verification: State of the Art and Challenges

Adequate monitoring of carbon sequestered by forestry activities is essential to the future of forestry as a climate change mitigation option. A wide range of approaches has been taken to monitor changes in forest carbon attributable to project activities. This paper describes simple, least-cost/least-precision methods, remote sensing, periodic carbon inventories, and traditional research methods. Periodic carbon inventories are the preferred approach because they are cost-effective, provide measurements with known levels of precision, and allow the monitoring of other values such as biodiversity and commercial timber volumes. Verification of monitoring estimates is discussed as an auditing process designed to evaluate reported carbon sequestration values. The limitations of remote sensing for biomass determination and the potential for changes in monitoring approaches due to improvements in technology are briefly reviewed.     

遥感方法应用于湖泊富营养化评价的研究

利用武汉东湖各子湖多年可靠的地面监测资料和1999年9月Landsat—7的TM各波段的卫星遥感数据,建立了各子湖的营养状态指数与TM各波段图像上灰度值之间的关系模型：一元线性模型、多元回归模型。运用这些模型对武汉各湖泊进行富营养化评价。同时基于地面监测资料,用日本学者相崎守弘提出的修正富营养化指数法对武汉主要湖泊的富营养化程度进行评价。结果显示,武汉湖泊多处于中富营养状态,遥感评价结果与地面监测结果基本一致。指出利用遥感方法进行湖泊水体富营养化监测评价是可行的、有效的、利用该方法可进行大范围的湖泊富营养化调查评价。     

遥感监测沙尘暴的研究进展及趋势

沙尘暴是一种气象灾害,也是严重的生态环境问题.它对自然环境和经济社会的危害已越来越引起人类的重视.随着环境遥感的发展,运用遥感技术对沙尘暴进行监测是最有效的方法之一.文章通过对中国沙尘暴遥感监测研究的现状的概述以及对当前遥感应用的技术水平的分析,展望了未来遥感监测沙尘暴的发展趋势.     

基于遥感和GIS技术的墨西哥湾溢油动态分析

利用多时相的遥感影像数据和地理信息系统(GIS)的空间分析功能,对2010年发生在墨西哥湾的溢油事故进行了动态监测,并结合洋流等信息对溢油漂移趋势进行了预测。结果显示,至2010年5月1日溢油面积已达到4月25日的4倍,并且溢油漂移趋势受到洋流的作用,漂移方向与洋流方向一致。研究表明,至5月1日对溢油处理与漏油处封堵的努力效果甚微,油污面积有继续扩大趋势,油污漂移方向与洋流具有较强相关性。该研究验证了光学遥感图像可以很好地对溢油事故造成的溢油范围进行监测,结合GIS的空间分析功能和洋流等信息可对溢油面积和溢油漂移趋势进行监测与分析,从而为溢油控制与清理提供重要参考信息。     

基于高分1号卫星和地面实测数据的杭州湾河口湿地植物物种多样性研究

遥感监测河口湿地植物物种多样性对于湿地生态环境的保护具有重要意义,利用遥感卫星准确反演湿地植物物种多样性一直是研究的难点。研究以杭州湾河口湿地植物为研究对象,利用地面实测数据,采用植物物种丰富度指数和Simpson指数分析了该湿地植物物种多样性水平。结合高分1号卫星影像,运用半变异函数对该区域植物物种多样性进行了空间异质性分析,探讨了高分1号卫星归一化植被指数（NDVI）用于湿地植物物种多样性监测的最佳遥感尺度,分析该植被指数与植物物种多样性指数的相关性,构建和应用了杭州湾河口湿地植物物种多样性遥感监测模型。结果表明：高分1号卫星NDVI监测湿地植物物种多样性的最佳尺度为19×19像元,利用该尺度及构建的遥感监测模型所得到的杭州湾河口湿地植物物种多样性水平与实际情况相吻合。研究证明利用高分1号卫星可快速有效地监测杭州湾河口湿地植物物种多样性水平。     

基于改进光谱角法的红树林高分遥感分类方法研究

传统影像分类方法多利用影像端元光谱进行地物分类,影像的空间结构信息被忽视,本研究结合面向对象分类方法思想以提高红树林遥感分类精度。本研究提出了一种结合端元类型选择、像元提纯等混合像元分解手段及分水岭图像分割算法的改进光谱角影像分类方法,并以山口红树林国家级自然保护区为研究区,利用GF-1号遥感影像数据,在光谱特征分析和地面调查的基础上,对红树林生态系统进行分类,并对分类精度进行分析。研究结果表明:改进的光谱角分类方法对GF-1影像分类效果较好,既兼顾地类光谱组成较复杂时的特殊性,又有效避免结果的破碎化现象,且总体精度达到95%（KAPPA系数0.944）,证明了其在红树林遥感影像分类及信息提取方面的应用潜力,为红树林生态系统业务化遥感监测奠定了基础。     

煤矿区土地修复的生态系统服务功能改善研究

采用3S技术,对我国典型的煤炭资源枯竭型城市石嘴山市煤炭开采区的生态修复前后的生态系统服务进行了分析。采用2001年与2011年两期LandsatETM和TM遥感影像图的人工解译与变化监测,分析了煤矿区的土地利用覆盖变化。并通过建立响应的评价指标体系,对其成功的治理煤矸石山,改造塌陷区,建立煤矿地质公园,将塌陷区改善为生态湿地等活动的生态系统服务功能变化进行了全面定量化评价。研究表明,通过10年的土地修复,采矿迹地的生态恢复能够提高其生态系统服务功能10倍左右,尤其是环境美学功能受到社会广泛认同。     

基于FY3C地表温度重建的多云地区旱情监测评估

受热红外传感器无法探测云下地表信息的影响,热红外遥感数据失去了对多云地区旱情监测的能力。采用RSDAST（Remotely Sensed Daily Land Surface Temperature Reconstruction）模型实现了FY3C/VIRR（Visible and Infrared Radiometer）云像元LST值的重建,结合重建后LST和NDVI数据采用TVDI指数对2018年重庆市干旱进行监测分析,并通过对比土壤墒情数据与OTVDI（Original TVDI）和RTVDI（Reconstructed TVDI）间的相关性来评估RTVDI在多云条件下旱情监测的能力。评估结果表明：基于RSDAST模型扩大了多云地区遥感干旱监测的空间范围和时间连续性,提升了区域旱情监测的精度（长时间序列和空间分布上RTVDI与土壤墒情数据间的R值均高于OTVDI）,极大地提高热红外遥感数据在多云条件下的可用性和可靠性。     

遥感技术在大尺度、动态环境监测中的应用

遥感具有宏观、快速和动态的特点.本文介绍了遥感技术基本原理、分类方法和不同遥感技术在环境监测中的用途,并据此阐述了遥感技术在不同的环境监测领域中的应用状况.本文还简要的概括说明了遥感技术在中国环境监测领域中的应用现状,指出了其存在的问题,对遥感技术在环境监测中的发展前景做了展望.     

基于热红外遥感数据和光谱混合分解模型的城市不透水面估算

不透水面的迅速增长是城市化的显著特征之一,针对大范围的城市监测,运用遥感技术迅速提取城市不透水面是当前国内外研究的热点。论文选用Landsat 7的ETM+影像,基于光谱混合分解模型,结合热红外遥感数据反演生成的地表温度,研究杭州市的不透水面分布信息的提取。通过高、低反照率、植被及土壤4类光谱端元的线性组合来表征不同城市土地类型,并利用地表温度和土壤分量分别剔除高、低反照率分量中的"噪声",综合修正后的高反照率分量和低反照率分量估算杭州市不透水面分布。结果显示,研究区中均方根误差的平均值为0.003 6,不透水面分布结果与同期Google earth上的高分辨率影像和SPOT 4影像的解译结果对比分析,绝大多数样本的估算值与解译值之差落在±0.15区间内,精度令人满意。研究表明,热红外遥感数据和光谱混合分解模型相结合,可以实现对不透水面进行快速、精确的估算。