Ling Chang

Ling Chang
University of Twente | UT · Department of Earth Observation Science (EOS)

Doctor of Philosophy

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55
Publications
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792
Citations

Publications

Publications (55)
Article
Full-text available
Mountainous landscapes affected by strong earthquakes typically exhibit higher landslide susceptibility in post-seismic periods compared to pre-seismic conditions. This concept is referred to as the earthquake legacy effect, which needs to be better understood to develop an accurate post-seismic landslide hazard assessment. The earthquake legacy ef...
Article
Full-text available
Shadows are a special distortion in synthetic aperture radar (SAR) imaging. They often hamper proper image understanding and target recognition but also offer useful information, and therefore, the statistical modeling of SAR image shadows is imperative. In this endeavor, we systematically deduced the statistical models of shadows in multimodal SAR...
Article
Full-text available
Mapping arable field areas is crucial for assessing agricultural productivity but poses challenges in sub-Saharan agroecosystems because of diverse crop calendars, small and irregularly shaped fields, persistent cloud cover, and lack of high-quality model training data. This study proposes several methodological improvements to overcome these chall...
Article
Full-text available
A R T I C L E I N F O Edited by Jing M. Chen Keywords: Hillslope deformation InSAR Prediction Line-of-sight velocity Multivariate regression Sentinel-1 Spatio-temporal model A B S T R A C T Spatiotemporal patterns of earth surface deformation are influenced by a combination of the geologic, topo-graphic, seismic, anthropogenic, meteorological and c...
Conference Paper
Full-text available
Strong earthquakes not only induce co-seismic mass wasting but also exacerbates the shear strength of hillslope materials and cause higher landslide susceptibility in the subsequent years following the earthquake. Previous studies have mainly investigated post-seismic landslide activity mainly by using landslide inventories. However, landslide inve...
Chapter
The exploration of the planetary surfaces from the synthetic aperture radar (SAR) is prominently being used in the characterization of the physical properties of the regolith. The Mini-SAR of Chandrayaan-1 and Mini-RF of the lunar reconnaissance orbiter were the first to operate in S-band in the hybrid polarimetric mode, whereas the dual-frequency...
Article
Full-text available
Extracting meaningful attributes of radar scatterers from SAR images, PAZ in our case, facilitates a better understanding of SAR data and physical interpretation of deformation processes. The attribute categories and attribute extraction method are not yet thoroughly investigated. Therefore, this study recognizes three attribute categories: geometr...
Preprint
Full-text available
Strong earthquakes are not only able to change the earth's surface processes by triggering a large population of coseismic landslides but also by influencing hillslope deformation rates in post-seismic periods. An increase in post-seismic hillslope deformation rates could also be linked to a change in post-seismic landslide hazard level and, thus,...
Preprint
Full-text available
Mountainous landscapes affected by strong earthquakes exhibit relatively higher landslide susceptibility in post-seismic periods compared to pre-seismic conditions. This concept is referred to as the earthquake legacy effect and is mainly examined by monitoring either rapid landslide occurrences or slow-moving landslides over time. To provide a mor...
Article
Studies of the lunar surface from Synthetic Aperture Radar (SAR) data have played a prominent role in the exploration of the lunar surface in recent times. This study uses data from SAR sensors from three Moon missions: Chandrayaan-1 Mini-SAR, Lunar Reconnaissance Orbiter (LRO) Mini-RF and Chandrayaan-2 Dual Frequency Synthetic Aperture Radar (DFSA...
Article
The Groningen gas field, the largest natural gas field in Europe, was discovered in 1959 and started its production in 1963. The Earth surface above it experienced subsidence over the past six decades because of gas extraction activities. To accurately reveal this surface movement with satellite SAR data, our study first proposes and demonstrates a...
Article
Full-text available
Sinkholes exhibit precursory deformation patterns. Such deformation patterns can be studied using InSAR time-series analysis over constantly coherent scatterrers (CCS). In the past we identified Heaviside and Breakpoint changes as two important forms of anomalous behavior. It is challenging to efficiently detect and classify these sudden step and s...
Conference Paper
Recently, we have shown that sinkholes can be characterized at an early stage by precursory deformation patterns from InSAR time series [1]. These patterns are often related to sudden changes in deformations or deformation velocities. With such a priori information, accurate deformation modelling and early detection of precursory patterns is feasib...
Article
Full-text available
Sinkholes are sudden disasters that are usually small in size and occur at unexpected locations. They may cause serious damage to life and property. Sinkhole-prone areas can be monitored using Interferometric Synthetic Aperture Radar (InSAR) time series. Defining a pattern using InSAR-derived spatio-temporal deformations, this study presents a sink...
Article
Full-text available
Synthetic aperture radar (SAR) missions with short repeat times enable opportunities for near real-time deformation monitoring. Traditional multitemporal interferometric SAR (MT-InSAR) is able to monitor long-term and periodic deformation with high precision by time-series analysis. However, as time series lengthen, it is time-consuming to update t...
Article
Full-text available
In order to effectively detect the detailed subsidence of tattered ground surface composed of many small fragments with the distributed scatterer interferometric synthetic aperture radar (DSInSAR) technique, a fast and accurate distributed scatterer extraction (FADSE), as an improved distributed scatterers extraction algorithm, is proposed and demo...
Article
A recent development in Interferometric Synthetic Aperture Radar (InSAR) technology is integrating multiple SAR satellite data to dynamically extract ground features. This paper addresses two relevant challenges: identification of common ground targets from different SAR datasets in space, and concatenation of time series when dealing with temporal...
Article
Full-text available
In this contribution, we investigate PAZ co-polarimetric SAR data applicability for surface movement mapping and scattering characterization. PAZ simultaneously collects SAR imagery in both VV and HH channels. Using a small stack of PAZ data, we apply the real-valued impulse response function correlation to identify constantly coherent scatterers (...
Article
Full-text available
Atmospheric heterogeneity mainly exposes itself as tropospheric phase delay in satellite interferometric synthetic aperture radar (InSAR) observations, which smears or even overshadows the deformation component of InSAR measurements. In this study, we estimated the performance of four global atmospheric models (GAMs), i.e. ERA5, ERA-Interim (ERA-I)...
Article
Full-text available
Satellite radar interferometry (InSAR) techniques have been successfully applied for structural health monitoring of line-infrastructure such as railway. Limited by meter-level spatial resolution of Sentinel-1 satellite radar (SAR) imagery and meter-level geolocation precision, it is still challenging to (1) categorize radar scatterers (e.g., persi...
Article
Full-text available
This study investigates the use of Advanced Land Observing Satellite 2 (ALOS-2) equipped with an enhanced L-band SAR sensor imagery alongside with Landsat-8 optical sensor in detection and mapping of burnt and unburnt scars occurring after a bushfire in Victoria, Australia. The bushfires had recently occurred in the period of 2018–2019. The analysi...
Preprint
Full-text available
Snow depth (SD) and Snow Water Equivalent (SWE) constitute essential physical properties of snow and find extensive usage in the hydrological modelling domain. However, the prominent impact of the hydrometeorological conditions and difficult terrain conditions inhibit accurate measurement of the SD and SWE— an ongoing research problem in the cryosp...
Article
Satellite-based persistent scatterer satellite radar interferometry facilitates the monitoring of deformations of the earth's surface and objects on it. A challenge in data acquisition is the handling of large numbers of coherent radar scatterers. The behavior of each scatterer is time dependent and is influenced by changes in deformation and other...
Article
Full-text available
Multi-temporal interferometric synthetic aperture radar (MT-InSAR) can be applied to monitor the structural health of infrastructure such as railways, bridges, and highways. However, for the successful interpretation of the observed deformation within a structure, or between structures, it is imperative to associate a radar scatterer unambiguously...
Article
Unexpectedly occurring sinkholes caused by shallow submerged voids are one of the key problems of intensively built-up post-mining areas. Five percent of Poland’s territory is still under the influence of post-mining deformation. Impending sinkholes, which tend to develop randomly over very large areas, cannot be detected by using traditional geoph...
Conference Paper
Full-text available
Snow depth (SD) is an important physical property of snow which is predominantly utilized in hydrologic studies. However, due to the terrain difficulties and hydrometeorological conditions, accurate large-scale SD estimation is still an ongoing research element in the cryosphere domain. Spaceborne synthetic aperture radar (SAR) systems have been e...
Conference Paper
Full-text available
The estimation of fresh snow depth (FSD) using X-band synthetic aperture radar (SAR) is feasible but challenging depending on the hydrometeorological conditions and data availability. In this study, the FSD is computed for the Beas river watershed in the northwestern Himalayas near Manali, India. It incorporates the recent copolar phase difference...
Article
Full-text available
Multi-temporal interferometric synthetic aperture radar (MT-InSAR) is used for many applications in earth observation. Most MT-InSAR methods select scatterers with high coherence throughout the entire time series. However, as time series lengthen, inevitable changes in surface scattering lead to decorrelation, which systematically decreases the num...
Conference Paper
Recent studies have revealed that variations in glacier movement over larger time scales can be explained by the changes in total mass of the glacier, making it an effective indicator of glacier health. It is vital to obtain precise and accurate glacier movement velocity to investigate the glacier health. Satellite based Differential SAR (Synthetic...
Thesis
Full-text available
Snow depth (SD) and Snow Water Equivalent (SWE) are two of the essential physical properties of snow. These are extensively used in the hydrological modelling domain for various avalanche and snow-melt runoff simulations. However, accurate large-scale measurement of the SD and SWE is still an ongoing research problem in the cryosphere paradigm due...
Article
Full-text available
Continuous hydrocarbon production and steam/water injection cause compaction and expansion of the reservoir rock, leading to irregular downward and upward ground movements. Detecting such anthropogenic ground movements is of importance, as they may significantly influence the safety and sustainability of hydrocarbon production activities, in partic...
Article
Full-text available
Satellite radar interferometry (InSAR) is an emerging technique to monitor the stability and health of line-infrastructure assets, such as railways, dams, and pipelines. However, InSAR is an opportunistic approach as the location and occurrence of its measurements (coherent scatterers) cannot be guaranteed, and the quality of the InSAR products is...
Article
Full-text available
Transition zones in railway tracks are locations with considerable changes in the rail-supporting structure. Typically, they are located near engineering structures, such as bridges, culverts and tunnels. In such locations, severe differential settlements often occur due to the different material properties and structure behavior. Without timely ma...
Conference Paper
In persistent scatterer (PS) interferometry, the relatively poor 3D geolocalization precision of the measurement points (the scatterers) is still a major concern. It makes it difficult to attribute the deformation measurements unambiguously to (elements of) physical objects. Ground control points (GCP's), such as corner reflectors or transponders,...
Article
Full-text available
Satellite synthetic aperture radar interferometry (InSAR) has the capability to monitor railway tracks and embankments with millimeter-level precision over wide areas. The potential of detecting differential deformation along the tracks makes it one of the most powerful and economical means for monitoring the safety and stability of the infrastruct...
Article
Full-text available
Multitemporal interferometric synthetic aperture radar (InSAR) is increasingly being used for Earth observations. Inaccurate estimation of the covariance matrix is considered to be the most important source of error in such applications. Previous studies, namely, DeSpecKS and its variants, have demonstrated their advantages in improving the estimat...
Article
Full-text available
Climate change and human involvement are changing the dynamics of permafrost environments, with potential impact on the safety and stability of infrastructure. The Qinghai–Tibet Railway (QTR) has been designed to withstand the dynamic permafrost conditions. Yet, in situ measurements of the track stability at elevations of about 5 km are scarce. Her...
Article
Full-text available
Monitoring the kinematic behavior of enormous amounts of points and objects anywhere on Earth is now feasible on a weekly basis using radar interferometry from Earth-orbiting satellites. An increasing number of satellitemissions are capable of delivering data that can be used to monitor geophysical processes, mining and construction activities, pub...
Article
Full-text available
The feasibility of monitoring the stability of railway infrastructure using dedicated satellite radar observations is demonstrated. These measurements are able to detect mm-level changes in the track geometry with a biweekly measurement update and a high spatial resolution by using interferometric synthetic aperture radar (InSAR) techniques. When d...
Conference Paper
Conventional PSI technology is aimed towards estimating displacement time series of persistently coherent scatterers (PS) from a given set of radar acquisitions. Whenever the data from a new acquisition become available, the estimators for the parameters of interest will be computed by re-adjustment of the system of equations. This strategy of batc...
Conference Paper
Persistent Scatterer Interferometry (PSI) has emerged over the last decade as a technique capable of very accurate (millimetric) measurements of ground deformation occurring at radar scatterers (persistent scatterers or PS) that are phase coherent over a period of time. PSI studies using C-band SAR data have shown that the PS spatial density in urb...

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