D-InSAR技术在矿山沉陷和地面沉降监测中的应用

差分雷达干涉(D-InSAR)测量技术,是合成孔径雷达(SAR)卫星应用的一个拓展。雷达图像的差分干涉图可用于监测厘米级或更微小的地面形变,具有全天候、大面积监测地面沉降和矿山沉陷的优势,本文以武安矿山沉陷和沧州市地面沉降监测为例,介绍了这一新技术在灾害监测领域中的实际应用。     

DInSAR与SBAS InSAR矿区地面沉降监测能力对比分析与验证

DInSAR与SBAS InSAR是目前常用于矿区地面沉降监测的两种InSAR技术.以山东济南某矿区地面沉降为研究对象,利用DInSAR、SBAS InSAR对覆盖该矿区的28景Sentinel-1A SAR影像进行处理,获取2018年07月至2019年06月期间的矿区地面沉降信息,利用矿区工作面开采信息与同时期水准监测数据,定性和定量地对比、分析和验证了这两种InSAR技术的矿区地面沉降监测精度和能力.研究发现,在沉降边缘区域,DInSAR和SBAS InSAR的监测结果与水准监测结果之间的差异较小,能较好反映矿区沉降的实际情况,而在沉降中心区域,二者的监测结果与水准监测结果有较大差异,监测能力不足.相比较而言,DInSAR技术在矿区沉降中心的快速大形变监测中更可靠,SBAS InSAR技术在矿区周边缓慢微小形变监测中精度更高.DInSAR和SBAS InSAR监测到的沉降值与水准监测结果之间的绝对差值曲线呈现出沉降漏斗边缘小、中心大的特征,这一发现可为后续研究DInSAR和SBAS InSAR监测结果的校正方法提供重要参考.     

基于D-InSAR的1993-1995年苏州市地面沉降监测

本文利用欧洲空间局ERS-1/2 SAR数据,通过SAR差分干涉测量(D-InSAR)处理得到1993-1995年苏州市地面沉降场测量值.地面水准测量数据的验证分析表明,差分干涉测量值与水准测量值的相关度达0.943,标准误差均值为0.1706.雷达差分干涉测量精度可达5mm(以水准测量代表地面形变的真实情况).研究结果表明,D-InSAR技术进行城市地面沉降方面监测和时空演化特征研究具有很大的优势,同时可用于其它类型城市地质灾害的监测.     

京津高铁北京段地面沉降监测及结果分析

京津高铁是我国第一条高速运行的城际铁路,其安全运行对轨道变形有着严格的要求.京津高铁北京段经过平原区的沉降区域.地面沉降,尤其是不均匀地面沉降已经引起了部分地段路基和桥梁变形,威胁着高铁的运营安全.因此,需要高精度监测铁路路基和桥梁沉降,分析其原因,进而才能提出缓解沉降灾害的合理措施,保证京津高铁安全运行.本文采用时序干涉测量技术、水准测量技术和分层标监测、地下水分层监测手段相结合,对京津高铁北京段地面沉降进行监测,并利用监测结果分析其差异性沉降成因.结果表明:沿线区域地面沉降发展一定程度上受到来广营凸起、南苑—通县断裂和大兴隆起构造控制;地下水超采是区域地面沉降的主要驱动因素,同时第四系沉积环境、地层岩性和补给条件等共同作用,使得地面沉降发展在空间上存在一定差异性,可以分为微小沉降区(DK0-DK9段)、严重沉降区(DK9-DK27段)和一般沉降区(DK27-DK50);沿线区域地面沉降主要贡献层为中深部地层(50~147.5 m),该层黏性土厚度较大,且主要呈现弹塑性形变,占总沉降量的76%左右,是未来地面沉降调控的主要层位.     

L波段InSAR数据观测的北京及其周边2007—2010年间累计地壳形变基本特征

地壳形变是评估地震灾害和地质灾害的重要依据之一。 北京及其周边地区的形变状况一直以来缺乏全面、 可靠的观测数据, 阻碍了对该地区这两种灾害的客观认识。 本研究利用L波段InSAR形变观测数据, 调查北京及其周边190 km×150 km范围内, 约3年时间内的累积地壳形变, 详细给出北京地区2007—2010年间的地壳形变基本特征, 为认识该地区的灾害提供参考。 研究结果显示, 该地区主要地壳形变源为地下水开采造成的地面沉降, 观测时间内累积的最大雷达视线向形变达到了37.6 cm。 地面沉降的严重影响, 以及大气噪声的干扰, 造成活动构造变形很难从现有数据定量分辨出来, 但可以确定在此观测期间内较大尺度(长度>50~100 km)的断层活动及其构造变形比较微弱, 对北京地区的地壳形变贡献较小。 最重要的一点是, 北京地区的地壳形变呈条块状分布, 清晰显示地面沉降与活动构造, 特别是NW走向的南口—孙河断层, 存在较强的相关性。     

激光实时干涉计量技术和雷达差分干涉技术测量形变的对比研究及其意义

分别叙述了激光干涉技术和雷达差分干涉技术的原理及应用. 采用激光实时干涉计量技术实验室观测试样在加压过程中的形变,研究不同破裂孕育区所表现的不同应变异常场特征. 采用雷达差分干涉技术可以测量地形及地表形变,并且有西藏玛尼、张北——尚义等地震前后的形变测量结果. 指出激光实时干涉计量技术与雷达差分干涉技术相似,都是以条纹变化图研究形变异常场特征. 因此, 对雷达差分干涉技术测量的孕震过程中的形变场,特别是临近大震发生前的形变场特征进行观测和以激光干涉技术进行实验及对比研究均将很有意义.      

基于GPS和MODIS的ENVISAT ASAR数据干涉测量中大气改正方法研究

GPS数据用于改正InSAR中大气延迟误差的方法受GPS站点密度的限制,只利用有限的几个站点所观测到的大气数据来生成干涉图的大气改正图,往往达不到很好的效果.本文研究利用GPS与MODIS数据的联合使用来生成大气改正图,首先用GPS数据对MODIS水汽产品进行分块校准,并且对MODIS水汽数据进行了空间结构函数分析,得到研究区域内水汽场的空间分布规律.然后把这种区域水汽场的空间分布信息结合到Kriging内插法中生成更为合理的水汽图.通过上海地区ENVISAT ASAR数据的实验发现,这种加以改正的GPS和MODIS数据联合改正法不仅可以对长波大气信号有明显的消弱,还能消弱一些短波的大气信号,特别是一些幅度较强的短波信号;经过GPS+MODIS算法改正后,短波信号占优和长波信号占优的两幅差分大气延迟图的整体RMS分别降低了32.74%和38.82%,去除幅度较大.与GPS+ATM(大气传输模型)算法比较,我们发现,在上海地区有限的数据条件下（即研究区域内只有6个GPS点）,GPS+MODIS法在大气去除效果或者说大气信号重现能力方面优于GPS+ATM算法.GPS+MODIS算法在捕获短波大气信号方面要比GPS+ATM更有优势,因此也可以改正短波大气误差.     

Simulating pumping-induced regional land subsidence with the use of InSAR and field data in the Toluca Valley, Mexico

A multidisciplinary approach is presented here for quantifying land subsidence in a heavily pumped aquifer system with complex stratigraphy. The methodology consists in incorporating Terzaghi’s 1D instantaneous compaction principle into a 3D groundwater flow model that is then applied and calibrated to reproduce observed hydraulic heads and compaction for the Toluca Valley, Mexico. Differential Interferometric Synthetic Aperture Radar (D-InSAR), a generated 3D-geological model, extensometers, monitoring wells, and available literature are used to constrain the model. The D-InSAR measured subsidence, extensometers, and numerical simulations of subsidence agree relatively well. Simulations show that since regional subsidence began in the mid 1960s there has been up to 2 m of subsidence in the industrial corridor, where heavy pumping and thick clay layers are found. This study shows that an approach using various sources of data is useful in estimating and constraining the vertical component of the inelastic skeletal specific storage.     

太原盆地地面沉降时序InSAR监测与季节性变形小波分析

太原盆地长期过量超采地下水,区域地下水位持续下降,导致了严重的地面沉降. 地面沉降的时空演变特征与地下水位的动态演化具有很强的相关性. 本文使用2015—2020年的Sentinel-1卫星数据进行时序SBAS-InSAR处理,获取了太原盆地地表形变速率和时间序列,并采用季节性形变模型分离形变时间序列中的线性趋势和季节性周期信号. 基于小波变换分析方法,定量分析了地表沉降与地下水位的周期演化特征以及两者之间的时间滞后关系. 研究发现：(1)地面沉降主要发生在太原盆地中部(小店—清徐—交城—祁县—太谷一带,速率达到-70.0 mm·a^-1)、西侧边山(清徐—交城一带,速率达到-63.4 mm·a^-1)和南部(孝义—介休一带,速率达到-72.2 mm·a^-1);(2)由于地下水压采和“引黄入晋”引水工程等一系列水资源管理措施的实施,太原市区地下水位回升,地面由沉降转变为抬升,整体抬升速率约9 mm·a^-1;(3)太原盆地中部(清徐—祁县—太谷一带)地表形变随着地下水位的季节性“开采—补给”作用而呈现出明显的“沉降—反弹”周期变化特征,年周期形变振幅达到26.2 mm;(4)盆地内季节性地表形变和地下水位变化之间的时间滞后关系不明显(仅为22天),说明该区域低渗透粘土对延缓含水层系统压实的影响有限. 本文结果可为太原盆地地面沉降防控和水资源可持续开采利用方案的制定提供科学依据.

     

利用GPS与InSAR研究西安现今地面沉降与地裂缝时空演化特征

西安孕育严重的地面沉降及地裂缝灾害,严重制约着城市的现代化发展,本文采用GPS精密定位和InSAR遥感差分技术对西安地面沉降和地裂缝进行变形监测与分析,获取了西安地面沉降与地裂缝整体变形现状的珍贵信息,通过对这些变形信息的研究分析,揭示了西安现今地面沉降与地裂缝时空演化特征和机理：随着停止或限采地下水,西安地面沉降量级由20世纪90年代中期的最大年沉降速率20～30 cm/a减少到不足10 cm/a,且超过60%的沉降区域的年沉降速率已由90年代中期的5~8 cm/a减少到不足2 cm/a;原有的沉降中心大部分已不存在或大大减小;地裂缝在时空活动与分布上与地面沉降存在明显的关联性;地面沉降和地裂缝随着西安高新区的建设向南、西南、东南逐步扩展.     

双极化Sentinel-1数据在昆明市沉降监测中的应用

针对多数学者用VV极化的Sentinel-1数据对城市区域进行监测而忽略VH极化数据的问题,本文利用SBAS-InSAR方法,结合28景双极化(VV极化和VH极化)Sentinel-1数据,得到了昆明市2018年8月—2019年7月间的地面沉降情况,并且对两种极化的沉降监测结果进行对比.结果表明昆明市主城区存在着较为明显的沉降现象,部分区域沉降严重形成明显的沉降漏斗.最大年平均沉降速率达到-53.63 mm/a(VV极化)和-53.67 mm/a (VH极化).对两种极化的数据集进行对比,发现在SDFP点的筛选和获取方面,VV极化数据集要优于VH极化数据集;其次,VV极化数据和VH极化数据的沉降速率、沉降分布及趋势等结果呈现出一致性,但是二者在同一时间段的各个监测节点的沉降时序变化存在着差异.     

Inverse modelling using PS‐InSAR data for improved land subsidence simulation in Las Vegas Valley,Nevada

Las Vegas Valley has had a long history of groundwater development and subsequent surface deformation. InSAR interferograms have revealed detailed and complex spatial patterns of subsidence in the Las Vegas Valley area that do not coincide with major pumping regions. This research represents the first effort to use high spatial and temporal resolution subsidence observations from InSAR and hydraulic head data to inversely calibrate transmissivities (T), elastic and inelastic skeletal storage coefficients (S_ke and S_kv) of the developed‐zone aquifer and conductance (CR) of the basin‐fill faults for the entire Las Vegas basin. The results indicate that the subsidence observations from InSAR are extremely beneficial for accurately quantifying hydraulic parameters, and the model calibration results are far more accurate than when using only groundwater levels as observations, and just a limited number of subsidence observations. The discrepancy between distributions of pumping and greatest levels of subsidence is found to be attributed to spatial variations in clay thickness. The Eglington fault separates thicker interbeds to the northwest from thinner interbeds to the southeast and the fault may act as a groundwater‐flow barrier and/or subsidence boundary, although the influence of the groundwater barrier to this area is found to be insignificant. Copyright © 2016 John Wiley & Sons, Ltd.     

Assessment of the mapping capabilities of ERS-1 SAR data for flood mapping: a case study in Germany

GAF examined, under contract to DARA (German Space Agency), the applicability of ERS-1 SAR data for flood mapping under operational conditions. The flood event investigated was the flooding in the Rhine valley in winter 1993–1994. In order to carry out an examination close to the end-user needs, the specific user requests concerning information about flood events were identified. The mapping accuracy in view of the flood extent and the flood level, the production of flood maps as well as the demonstration of the runoff turned out to be the most interesting points. The specific user information needs were considered in the project objectives to define the applicability as well as the deficits of ERS-1 data concerning an operational use for flood mapping. After a detailed analysis of the time aspects of the traditional mapping method and a satellite data analysis, a visual interpretation as well as an automatic classification were applied, including various filter steps to derive the flood boundary. As a result, the visual interpretation proved to be the more accurate method. Crucial domains for both the visual interpretation and the automatic classification turned out to be settlements, forests and bushes as well as regions with layover and foreshortening effects. The comparison between the flood level derived from satellite data and the flood level registered by the water authority boards brought a height difference which ranged between 0·5 and 2·0 m. The relatively coarse resolution and problems with correct interpretation of the flood line proved to be the reason for this difference. In general the results are convenient, but in relation to field measurements of the water level they are too inaccurate. A cost and benefit analysis as well as a proposal for an operational GIS system using ERS-1 SAR data are still under investigation. © 1997 John Wiley & Sons, Ltd.     

Analysis of elastoplasticity and rheology due to mining subsidence

At present, as the easily mining resources are being increasingly depleted, the exploitation of coal under buildings, water-bodies and railways is imminent for the sustainable production. Probability in-tegral method is a general method for mining subsidence in the coal system. Because of poor under-standing of mining subsidence for other sections, the authors suggest probability integral method for the study of coal mining under buildings, water-bodies and railways. Moreover, the calculation result of probability integral method should be corrected by numerical simulation method. Based on practical projects, the impact has been evaluated on the security of Xifeihe left embankment under coal mining. Combining with the results of probability integral method, we propose that the 600 m far from em-bankment is a good rationality. This article provides the basis for the rational exploitation of coal re-source which is a major practical problem under the premise of Water Infrastructure Security. Fur-thermore, it also can be served as a reference for the similar projects, such as mining Xiaolangdi res-ervoir area, mining Yuecheng reservoir and mining the major channels of Middle Route South to North Water Transfer.     

Identification of potential subsidence related to pumping in the Almería basin (SE Spain)

Ground subsidence of detrital deposits in the Almería basin (SE Spain) was studied using the remote sensing technique of Differential Interferometry SAR (DInSAR). This basin is one of the most arid in Europe, receiving an average rainfall of 250 mm per year. Over the last 60 years the region has experienced an enormous agricultural and urban expansion, whose water demand has been largely supplied from groundwater, leading to the current situation of overexploitation of water resources. This paper outlines the likely relationship between groundwater abstraction and subsidence. To this end, 34 ERS and Envisat images, taken between 2003 and 2009, were analysed to estimate ground surface deformations, and hence, compared with water table variations measured in a number of piezometers in the basin. The analysis shows a clear parallelism between the variations in piezometric level and deformation of the ground surface. In addition, the zones of greatest subsidence coincide with those areas where groundwater abstractions are concentrated. Subsidence over the examined period varies from 10 to 30 mm, with extreme values as high as 50 mm, which translates to a rate of between 1·7 and 5 mm/year, reaching maximum rates of 8 mm/year at some points. Given such subsidence rates, damage to urban infrastructures are, for the moment, incipient. Copyright © 2011 John Wiley & Sons, Ltd.     

SAR遥感图像在汶川地震灾害识别中的应用/

汶川地震发生后,受阴雨天气的影响,光学遥感影像在救灾决策中的作用受到了很大的限制,而SAR 图像由于其全天候的特点成为这次抗震救灾前期遥感信息保障十分重要的数据源.采用ENVISAT 的ASAR 作为数据源,利用多时相的雷达数据的幅度及相位信息对映秀及周边地区做了地震灾害识别,其中利用震前震后的幅度图像做比值变化检测,在映秀镇及紫坪铺水库等山区取得了较好的效果;利用相位信息做干涉处理得到的相干图像,经过失相干分析,发现建筑物的破坏等级与相干系数变化指数的大小高度相关.比较这两种方法,在都江堰等平原地区由于失相干现象不像山区那么严重,并且利用比值处理可以去除部分空间失相干及系统热噪声等带来的干扰因素,可以成为幅度图像的有益补充.结果表明,结合SAR 幅度影像和干涉相干影像,可以在地震灾害评估中取得更好效果.随着极化干涉雷达技术的日益成熟,多时相幅度信息、相位信息等多特征SAR 影像信息的融合会在救灾决策中发挥更大的作用.