基于PS-InSAR的天津地区沉降监测及分析

城市地面沉降监测是保障城市安全建设和健康发展的重要手段之一,而传统的沉降监测方法无法大尺度反映地面形变信息。针对近几年天津地区出现大面积沉降现象,利用Sentinel-1A数据基于永久散射体干涉测量技术开展城区大范围沉降监测研究并分析了地面沉降原因。结果表明：近年来天津地区多处出现地面沉降,严重沉降区集中天津的武清区、北辰区以及郊区乡镇结合区域的王庆坨镇、胜芳镇、左各庄镇、静海镇以及大寺镇,其最大沉降漏斗位于王庆坨镇,沉降速率为-63.2 mm/a。经分析发现天津地面沉降与地下水过度开采、大型工业区的迁移和建设以及活动断裂带地质活动有关。     

基于PS-InSAR技术的廊坊市地面沉降监测研究

随着城市化进程的加速发展,地面沉降危害不断加剧。以廊坊市城区为示范研究区,选取近5 a的ENVISat卫星ASAR数据,采用永久散射体干涉测量(PS-InSAR)技术,提取廊坊市城区2003~2007年时间序列地面沉降形变信息,并对廊坊市地面沉降空间分布特征进行初步分析。研究结果表明:廊坊市城区年平均沉降速率在-19.2~18.7mm/a之间变化,沉降中心主要分布在城区北部地区,对城市基础设施及施工建设产生严重影响。     

基于PS-InSAR的天津地区沉降监测及分析

城市地面沉降监测是保障城市安全建设和健康发展的重要手段之一,而传统的沉降监测方法无法大尺度反映地面形变信息。针对近几年天津地区出现大面积沉降现象,利用Sentinel-1A数据基于永久散射体干涉测量技术开展城区大范围沉降监测研究并分析了地面沉降原因。结果表明：近年来天津地区多处出现地面沉降,严重沉降区集中天津的武清区、北辰区以及郊区乡镇结合区域的王庆坨镇、胜芳镇、左各庄镇、静海镇以及大寺镇,其最大沉降漏斗位于王庆坨镇,沉降速率为-63.2 mm/a。经分析发现天津地面沉降与地下水过度开采、大型工业区的迁移和建设以及活动断裂带地质活动有关。     

利用Sentinel-1A合成孔径雷达干涉时间序列监测陇东地区地面沉降变形

基于覆盖陇东地区同一轨道的97景Sentinel-1A卫星影像,在ISCE和StaMPS数据处理平台上利用PS-InSAR技术进行叠加数据处理,获得研究区自2014年10月至2019年5月的年平均地表LOS向形变场,并对形变场结果进行二维网格滤波处理,获取沉降中心的变化特征。研究结果表明：陇东地区主要存在两类形变,一类是由构造活动引起的地表形变,主要分布在海原断裂与六盘山东麓断裂转换区附近,跨海原断裂年平均形变约为1 mm/a,而六盘山东麓断裂附近断层无明显变形,鄂尔多斯块体内部变形微弱;另一类则是由人类工业活动,如煤矿开采、地下水开采活动等导致的地表沉降,主要影响区域为华亭矿区和宁正矿区,均呈现漏斗状沉降形态,年均最大沉降分别约为8 mm/a和30 mm/a。     

基于PSI技术的芜湖市地面沉降时空特征分析

城市的沉降监测有利于了解区域实时高程,可为地质灾害与防护部门提供数据依据,避免因高程损失而带来的地质灾害。基于2016年1月至2017年12月共22景Sentinel-1A干涉宽幅模式影像数据,利用永久散射体合成孔径雷达干涉测量技术以及合成孔径雷达差分干涉测量技术进行芜湖市地表形变监测,并分析研究区地面沉降的时空分布特征。空间上,阐述芜湖市地面沉降的整体格局,再以道路为专题,分析了道路的沉降分布格局。时间上,以时间为基线,逐月分析地面沉降部分在年内的具体变化。结果表明：空间上,芜湖市地面沉降主要集中在长江以东的范围,呈现出由西向东逐渐增加的趋势,长江以西呈现零星漏斗式沉降分布,其中,沉降累积量也与道路的密度与建设相关,道路汇集区与修建区域的沉降累积量较大;时间上,研究区整体沉降量各月变化较均匀,其中,沉降量变化范围在6月最大,10月与11月最小。     

基于PSI技术的芜湖市地面沉降时空特征分析

城市的沉降监测有利于了解区域实时高程,可为地质灾害与防护部门提供数据依据,避免因高程损失而带来的地质灾害。基于2016年1月至2017年12月共22景Sentinel-1A干涉宽幅模式影像数据,利用永久散射体合成孔径雷达干涉测量技术以及合成孔径雷达差分干涉测量技术进行芜湖市地表形变监测,并分析研究区地面沉降的时空分布特征。空间上,阐述芜湖市地面沉降的整体格局,再以道路为专题,分析了道路的沉降分布格局。时间上,以时间为基线,逐月分析地面沉降部分在年内的具体变化。结果表明：空间上,芜湖市地面沉降主要集中在长江以东的范围,呈现出由西向东逐渐增加的趋势,长江以西呈现零星漏斗式沉降分布,其中,沉降累积量也与道路的密度与建设相关,道路汇集区与修建区域的沉降累积量较大;时间上,研究区整体沉降量各月变化较均匀,其中,沉降量变化范围在6月最大,10月与11月最小。     

基于SARscape的干涉叠加在地表形变监测中的应用

地表形变主要表现为地震形变、地面沉降、山体滑坡等,由InSAR技术发展而来的干涉叠加通过挖掘时间序列SAR图像获取mm级的形变信息。本文介绍了干涉叠加技术的基本原理和技术流程、基于永久散射体的方法,利用2008年～2010年的23幅Cosmo-skymed数据对北京奥林匹克公园内的主要区域进行了地表形变的监测。     

基于PSI技术监测上海市2009年～2010年区域地表沉降

采用振幅和相位联合分析的PS探测方法,以上海市作为实验研究区,进行PSI城市地表沉降监测并对成因进行了详细分析。实验结果表明:①由于大规模的城市建设、地下水开采、工业化生产和交通运输等活动,研究区内最大沉降速率达-47mm/年,平均沉降速率达-16.96mm/年,地表沉降比较明显。②2008年以前的沉降中心得到有效控制,现阶段有3个沉降中心较为明显,即罗泾镇宝山工业园区,平均沉降速率为-29.8mm/年;虹口足球场,平均沉降速率为-24.58mm/年;闵行经济技术开发区,平均沉降速率为-32.2mm/年。③地表沉降随着城市建设的发展向北、南、西南、东南逐步扩展。④水准数据验证了监测结果,精度可达±6mm,表明PSI技术在城市地表沉降监测中具有很大的优势。     

雷达InSAR数据在矿山地表形变监测中的应用研究

针对矿山地表形变这一特殊区域，开展星载InSAR测量的研究工作，在大量调研的基础上确定技术流程和关键技术及解决方法，选择具有典型意义的河北武安地区，应用InSAP数据，采用三次、二次过境差分法处理，获得了几个时间间隔内矿山开采地表形变图像。经与实际对比应用效果较好。真实地反映了地表形变的动态信息。实践证明，利用InSAR数据进行地表形变动态监测有着重要的现实意义和广泛的应用前景。     

基于D-InSAR技术的矿区地表形变监测研究

本文利用时序Envisat单视复数据(SLC),分别采用"2轨法"和"3轨法"雷达差分干涉测量,对河北邯郸峰峰煤矿地区地表沉降检测试验,检测矿区内地表沉降发生的位置及范围,结合实验分析了差分干涉测量技术在地表形变监测中存在的问题及其应用前景.     

Surface deformation from persistent scatterers SAR interferometry and fusion with leveling data: A case study over the Choushui River Alluvial Fan, Taiwan

The Choushui River Alluvial Fan (CRAF), one of the most important agricultural areas in Taiwan, suffers severe subsidence caused by groundwater withdrawal. We use 20 ENVISAT images from 2006 to 2008 to derive vertical deformation over CRAF by persistent scatterer interferometry (PSI), which effectively reduces errors affecting conventional DInSAR techniques. The pixel density over CRAF is 107.6 pixels/km², compared to 0.19 points/km² of the leveling benchmarks. PSI yields vertical displacements matching the leveling result to 0.6 cm/year (RMS), and provides a higher spatial resolution of subsidence than the latter. We also develop a data fusion method that considers the high-precision, low point-density leveling result as a smoothed correction to the PSI result. The combined field is more representative of overall deformation characteristics than the PSI-only or leveling-only field, and it is better suited for the assessment of the impact of subsidence over CRAF.     

永久散射体雷达干涉研究综述

传统D|InSAR技术虽然在地表形变测量应用中得到广泛应用,但其测量精度容易受失相干、大气效应、DEM误差等的影响,测量结果有时甚至不可靠。为了突破这些限制,在D|InSAR技术中引入时间维,筛选出时序SAR图像上受失相干影响较小的像元,建立并解算相位模型,从而提取形变信息。PS|InSAR技术自出现以来,经过不断改进,在受失相干影响较大的长期缓慢形变监测中发挥了重要作用,一直是近年来雷达干涉领域研究的重点问题。详细梳理了PS|InSAR技术的发展历史,总结了关键技术环节的改进算法以及应用领域,指出现有PS|InSAR技术仍然存在的问题以及可能的发展趋势。     

多模式雷达在矿区沉降监测中的应用研究

合成孔径雷达差分干涉测量(DInSAR)技术在地表形变监测方面已得到广泛应用。介绍了将差分InSAR技术运用于矿区地表沉降监测,获得了河北峰峰煤矿地表Envisat/ASAR和ALOS/PALSAR的雷达形变干涉相位图,并对Envisat C波段和ALOS L波段的形变干涉相位图进行了相干特性和相位特性的分析。通过综合考虑C波段和L波段的优势与不足,将两者联合使用,实验表明利用多模式雷达数据对矿区地表沉降进行检测的可行性。同时,通过对雷达干涉相位图的分析,能够及时提供正在进行地下开采活动的矿区地理位置。     

Persistent Scatterers Interferometry detects and measures ground subsidence in Lisbon

Results from the application of Persistent Scatterers Interferometry in Lisbon Metropolitan Area revealed two previously unknown subsiding urban areas: one (Laranjeiras) is located in the center of Lisbon; another (Vialonga) is to be found toward the North, in an industrial region crossed by Lisbon's main highway and railway lines. The two subsiding sectors are bordered by sharp velocity gradients, and the subsidence pattern appears partially delimited by mapped geologic faults. Surface geology and urbanization alone are unable to explain the phenomena. In the Vialonga area, the historical record of water pore pressure shows a clear decline of the levels (up to 65 m in 27 years), providing evidence of over-exploitation of groundwater resources. Limited information from wells drilled inside and outside the subsidence area points to a spatial correlation between the subsidence and the water pressure levels, and suggests that faults could be acting as hydraulic barriers in the aquifer system. The surface subsidence detected is probably caused by compaction of a clay-rich Oligocene-aged aquitard, led by over-exploitation of adjacent aquifers. The same Oligocene aquitard layer is present in the Laranjeiras area, immediately bellow a multi-layered sand-clay-limestone Miocene aquifer, but further work is needed to diagnose the possibility of over-exploitation of groundwater here. In this work we were able to independently confirm the PSI results, by comparing autonomous PSI results processed for the same geographical areas, and by comparing PSI with leveling and continuous GPS derived subsidence velocities, whose close match provided further ground validation of the space-borne PSI technique.     

Potential of small-baseline SAR interferometry for monitoring land subsidence related to underground coal fires: Wuda (Northern China) case study

Uncontrolled coal fires can result in massive surface displacements due to the change in volume of burning coal and thermal effects in the adjacent rock mass; simultaneously, the resultant surface breakings provide greater access to air and water that in turn can aggravate the problem of underground coal seam burning. In this case study, we have investigated the feasibility and potential of detecting the land subsidence accompanying coal fires by means of satellite InSAR observations. Three groups of small-baseline InSAR approaches (PSI, stacking and 2-passDInSAR) were applied to the Wuda coalfield (Northern China) to reveal the spatial and temporal signals of the land subsidence in the areas affected by the coal fires. The interferometric results agree well with GPS observations and coal fire data obtained by field investigation, which demonstrates that the small-baseline InSAR techniques have remarkable potential to detect this land subsidence of interest. In particular, our results show that the development of coal fires can lead to new subsiding areas and also accelerate the ongoing surface subsidence, typically within the areas of mature coal fires, through a comparison of the interferometric observations and the multi-temporal coal fire maps. This timely and reliable information on land subsidence will be useful for the detection and mapping of the coal fire affected regions and thereby assist in fighting and controlling coal seam burning.     

COSMO-SkyMed数据在常州市地表形变监测中的应用

小基线集合成孔径雷达干涉测量技术(SBAS-InSAR)已成功应用于城市地表形变监测,并表现出极大的潜力和优势。X波段高分辨率雷达卫星在地表微小形变探测方面较C波段和L波段更为敏感。选取覆盖常州地区COSMO-SkyMed高分辨率SAR影像,采用SBAS-InSAR方法获得了地表形变时间序列,对比水准观测数据,分析了干涉测量结果的精度,根据历史地下水位监测数据,分析了地下水水位变化对地表形变的影响。结果表明:干涉测量结果与水准观测数据具有很好的一致性,沉降区域主要发生在武进区,最大沉降量超过-40mm,主城区出现了轻微的回弹现象,回弹达到+5mm;地下水水位持续上升与地面沉降减缓、地面回弹趋势一致,地下水水位变化仍然是常州市地表形变的主要影响因素。     

永久对象服务的研究和实现

结合对象管理组制定的永久对象服务标准,利用框架技术,针对多种对象类型和存储机制,介绍一种实现存储、恢复永久属性重构对象机制的通用办法,以满足现实世界中对象模型的要求。主要讨论框架的特点,在ＣＯＲＢＡ环境下永久对象服务的实现及对永久对象服务标准的理解。     

Surface subsidence and uplift above a headrace tunnel in metamorphic basement rocks of the Swiss Alps as detected by satellite SAR interferometry

Surface subsidence associated with the construction of a headrace tunnel in the Swiss Alps at more than 2000 m above sea level (a.s.l.) has been detected at two locations with satellite differential Synthetic Aperture Radar (SAR) interferometry. At the first location, a subsidence trough of about 4 cm in the satellite line-of-sight direction following the headrace tunnel axes has been measured between August 1995 and August 1996. Similar values from SAR data of ascending and descending orbits indicate displacements in the vertical direction of the movement. In the second case, a symmetric cone of depression with a maximum displacement of about 4 cm between 1995 and 1997 has been observed above the tunnel. Differences in the results from satellite SAR data of ascending and descending orbits indicate that the direction of displacement in this second case was not entirely vertical. Large-scale consolidation associated with pore-pressure reduction in the rock mass arising from tunnel drainage at about 200-400 m depth beneath the topographical surface is believed to be the contributing mechanism (Zangerl et al., 2008a, 2008b). Evidence for this process is based on pore pressure recordings in nearby deep wells. In both areas, the subsidence was followed by a small uplift of about one centimeter between 1997 and 1999, after the tunnel was cased with permeable concrete segments. This partial recovery is also visible in pore pressure records and can be related to the elastic components of rock mass deformation.