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Sentinel-1A TS-DInSAR京津冀地区沉降监测与分析 总被引：1，自引：1，他引：0
近年来,京津冀地区的不均匀地表沉降日趋严重,对公路、铁路等基础设施安全造成严重威胁,已引起国内外广泛关注。合成孔径雷达时序差分干涉TS-DIn SAR(Time Series Differential Interferometric Synthetic Aperture Radar)作为一种高效的广域形变测量手段,在地面沉降调查监测中已被广泛应用,但如何针对高现势性的影像数据高精准提取大范围区域地表形变是当前深化的热点。本文利用欧洲太空局发布的Sentinel-1A新型数据源,针对TOPS(Terrain Observation by Progressive Scans)模式影像间存在多普勒中心不一致问题,借助外部高精度POD(Precise Orbit Determination)轨道和DSM(Digital Surface Model)数据进行频移滤波迭代配准,并针对Sentinel-1A数据特征集成优化了基于点目标时序分析的大区域地表形变监测方法,以2015年—2016年期间的29景影像为实验数据开展了京津地区沉降监测研究,提取了北京东、廊坊及天津西等地区的沉降结果,并结合区域内典型区域人口密度、产业分布、地表覆盖和线路剖面等信息深入分析了沉降的时空分布特征和成因。结果表明,Sentinel-1A时序干涉结果在大范围地表沉降调查监测上具有可靠的应用精度。 相似文献
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Keren Amram 《Geochimica et cosmochimica acta》2005,69(10):2535-2546
The main goal of this paper is to propose a new rate law describing the combined effect of pH (1 to 4.5) and temperature (25 to 70 °C) on smectite dissolution rate, under far from equilibrium conditions, as a step towards establishing the full rate law of smectite dissolution under acidic conditions. Dissolution experiments were carried out using non-stirred flow-through reactors fully immersed in a thermostatic water bath held at a constant temperature of 25.0°C, 50.0°C or 70.0°C ± 0.1°C. Smectite dissolution rates were obtained based on the release of silicon and aluminum at steady state. The results show good agreement between these two estimates of smectite dissolution rate. Low Al/Si ratios were obtained in experiments that were conducted at pH ≥4. These low Al/Si ratios are explained by precipitation of gibbsite and/or diaspore.Dissolution rate increases with temperature and decreases with increasing pH. Dissolution rates of experiments in which ΔGr ≤ −21 kcal mol −1, are not affected by deviation from equilibrium. Dissolution rates in most experiments are not affected by the addition of up to 0.3 M NaNO3 to the input solution.A simple model is used to describe the combined effect of pH and temperature on smectite dissolution rate. According to this model, dissolution rate is linearly proportional to the concentration of adsorbed protons on the mineral surface, and proton adsorption is described using a Langmuir adsorption isotherm. All experimental results at pH <4 were fitted to the model using a multiple non-linear regression. The resulting rate law is:
(A1) 相似文献
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Stoichiometry of smectite dissolution reaction 总被引：1，自引：0，他引：1
The dissolution stoichiometry of smectite-rich bentonites SAz-1, STx-1 and SWy-1 was studied at 50°C and pH 2 and 3 using flow-through reactors. In addition to smectite, these samples contain considerable amounts of silica phases (quartz, cristobalite and/or amorphous silica). As a result, the molar Al/Si ratios of the bulk samples are significantly lower than those of the pure smectite.Smectite dissolution was highly incongruent during the first few hundred to few thousand hours of the experiments. Release rates of Si, Mg, Ca and Na underwent a distinct transition from an initial period of rapid release to significantly lower release rate at steady state. A reversed trend was observed for release of Al, which gradually increased from very low starting release rate to higher release rate at steady state. At steady state the ratio of released Al to released Si was found to be constant and independent of the experimental conditions. We suggest that this ratio represents the Al/Si ratio of the smectite itself, and it is not influenced by the presence of accessory phases in the sample.The rapid release of calcium, sodium and magnesium from the interlayer sites is explained by ion-exchange reactions, whereas the fast release of silicon is explained by dissolution of amorphous silica. We interpret the initial slow release of Al as the result of inhibition of smectite dissolution due to coating or cementation of the smectite aggregates by amorphous silica. As the silica is dissolved, the aggregates fall apart and more smectite surfaces are exposed, resulting in an increase in the smectite dissolution rate. Thereafter, the system approaches steady state, in which the major tetrahedral and octahedral cations of smectite are released congruently. 相似文献
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在各类边坡工程建设及矿山的开发与开采中,岩体边坡稳定与否是制约生产效益的主要因素之一.边坡变形失稳地质灾害给工程建设和生产造成的损失是巨大的,准确分析边坡变形失稳影响因素,建立科学合理的评价指标体系,及时准确地预报滑坡空间和规模,可最大限度减少灾害造成的损失,在区域规划、管理决策、灾害防治中有其重大的社会、经济意义. 相似文献
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研究一种基于GPS和惯导系统定位、多种传感器融合的车载交通标志调查系统。介绍系统的组成、传感器间的配准和定位方法。在此基础上,研究基于CCD影像的交通标志采集方法。并以实际工程为例,对基于车载测量的交通标志调查系统进行研究成果的验证。 相似文献
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The effect of the overlying water velocity on ammonium (NH4+) uptake by benthic biofilms was studied in a recirculating laboratory flume (260 cm long, 29 cm wide), packed with 5 cm of silica sand arranged into bedforms. NH4+ uptake was determined as the reduction in NH4+ concentration in the water at average overlying water velocities of 0.8, 2, 4 and 8 cm s?1. NH4+ uptake was relatively constant under laminar flow conditions but increased when the flow regime became turbulent (>4 cm s?1). This pattern was observed for two biofilms differing in their total biomass and in the abundance of the ammonia‐oxidizing bacteria, thus indicating that NH4+ uptake was strongly controlled by mass‐transfer processes. The near stoichiometric relationship between the rates of NH4+ uptake and nitrate (NO3?) accumulation suggests that aerobic nitrification was the main route for NH4+ uptake. Microelectrode measurements showed a sharp decline of oxygen concentrations and pH values within the biofilms, thus supporting strong nitrification activity within the surficial section of the benthic biofilms. The results of this study highlight the key role of hydrodynamic conditions in regulating NH4+ uptake in the transition from laminar to turbulent flow conditions. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
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正合成孔径雷达差分干涉(InSAR)测量技术是最近30年来发展迅速的空间对地观测技术。相对传统测量技术,该技术具有精度高、覆盖范围广、不受天气状况影响等优势,已在区域性沉降监测、灾害监测评估、能源资源勘查等非常广阔的领域展现了它的应用潜力。SAR卫星影像质量不够高是制约该技术精度提升和应用范围扩展的一 相似文献
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流动重力观测结果显示，地震孕育过程中重力变化最大处往往不与震中重合，美国科学家J.T.Kuo（郭宗汾）提出了孕震体质量变化中心震质源(hypocentroid)和其在地表的投影震质中(epicentroid)的概念．本文采用球、椭球和圆柱体等3种旋转体模型模拟孕震体，分别计算孕震体均匀膨胀引起的表面重力变化模型，并利用最小二乘法对1981～2000年发生在京津唐张测网内16次M>4.0地震进行震质中迭代反演. 计算精度表明，圆柱体模型为三者中的最隹模型．研究了震中、震质中与断层之间的位置关系，发现京津唐张地区M4~5地震震质中与震中的距离在0~40 km之间，震中一般发生在断层末端，或断层交汇处；而震质中大都发生在断层间的块体内，且成丛分布．这意味着区域内存在小范围的构造——地震孵化区，一次次地震在孵化区内孵化，但却在其周围发生．其间，断层的存在起着重要的控制作用． 相似文献