An Integrated InSAR and GNSS Approach to Monitor Land Subsidence in the Po River Delta (Italy)

Fabris, Massimo; Battaglia, Mattia; Chen, Xue; Menin, Andrea; Monego, Michele; Floris, Mario

doi:10.3390/rs14215578

Cited by 14 publications

(12 citation statements)

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“…The correlation values of the displacements were computed to determine the radius of this circle enclosing the GNSS station. ALOS-2 and Sentinel-1 datasets were found to have the highest correlation at points with a radius of 200 m. Fabris et al [ 8 ] also investigated the integration of GNSS and InSAR to monitor the land subsidence in the Po River Delta by determining the circle around the GNSS stations. They also selected a 200 m radius circle but without any statistical analysis.…”

Section: Resultsmentioning

confidence: 99%

“…A previous study by Bui et al [ 7 ] determined a diameter of 100 m around the GNSS station in the InSAR study carried out between 2016 and 2020. Fabris et al [ 8 ] determined the displacements of the detected Persistent Scatterer (PS) points in clusters of 50, 100, 150, and 200 m radii using Sentinel-1 and COSMO-SkyMed SAR data. In most of the studies in the literature, network solutions have been used to analyze GNSS observations.…”

Section: Introductionmentioning

confidence: 99%

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A Statistical Approach for the Integration of Multi-Temporal InSAR and GNSS-PPP Ground Deformation Measurements

Delen,

Sanli,

Abdikan

et al. 2023

Sensors

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Determining and monitoring ground deformations is critical for hazard management studies, especially in megacities, and these studies might help prevent future disaster conditions and save many lives. In recent years, the Golden Horn, located in the southeast of the European part of Istanbul within a UNESCO-protected region, has experienced significant changes and regional deformations linked to rapid population growth, infrastructure work, and tramway construction. In this study, we used Interferometric Synthetic Aperture Radar (InSAR) and Global Navigation Satellite System (GNSS) techniques to investigate the ground deformations along the Golden Horn coastlines. The investigated periods are between 2015 and 2020 and 2017 and 2020 for InSAR and GNSS, respectively. For the InSAR analyses, we used sequences of multi-temporal synthetic aperture radar (SAR) images collected by the Sentinel-1 and ALOS-2 satellites. The ground displacement products (i.e., time series and velocity maps) were then cross-compared with those achievable using the Precise Point Positioning (PPP) technique for the GNSS solutions, which can provide precise positions with a single receiver. In the proposed analysis, we compared the ground displacement velocities obtained by both methods by computing the standard deviations of the difference between the relevant observations considering a weighted least square estimation procedure. Additionally, we identified five circle buffers with different radii ranging between 50 m and 250 m for selecting the most appropriate coherent points to conduct the cross-comparison analysis. Moreover, a vertical displacement rate map was produced. The comparison of the vertical ground velocities derived from PPP and InSAR demonstrates that the PPP technique is valuable. For the coherent stations, the vertical displacement rates vary between −4.86 mm/yr and −23.58 mm/yr and −9.50 and −27.77 mm/yr for InSAR and GNSS, respectively.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

A Statistical Approach for the Integration of Multi-Temporal InSAR and GNSS-PPP Ground Deformation Measurements

Delen,

Sanli,

Abdikan

et al. 2023

Sensors

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“…In the past, PRD was affected by high values of land subsidence rates ( [14,36,37] and references therein). Currently, the phenomenon, even strongly reduced, is still ongoing [38][39][40], and most of the area lies below the mean sea level (in the order of 2-3 m), protected by earthen levees for hydraulic safety [41][42][43].…”

Section: The Study Areasmentioning

confidence: 99%

High-Resolution Real-Time Coastline Detection Using GNSS RTK, Optical, and Thermal SfM Photogrammetric Data in the Po River Delta, Italy

Fabris,

Balin,

Monego

2023

Remote Sensing

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High-resolution coastline detection and monitoring are challenging on a global scale, especially in flat areas where natural events, sea level rise, and anthropic activities constantly modify the coastal environment. While the coastline related to the 0-level contour line can be extracted from accurate Digital Terrain Models (DTMs), the detection of the real-time, instantaneous coastline, especially at low tide, is a challenge that warrants further study and evaluation. In order to investigate an efficient combination of methods that allows to contribute to the knowledge in this field, this work uses topographic total station measurements, Global Navigation Satellite System Real-Time Kinematic (GNSS RTK) technique, and the Structure from Motion (SfM) approach (using a low-cost drone equipped with optical and thermal cameras). All the data were acquired at the beginning of 2022 and refer to the areas of Boccasette and Barricata, in the Po River Delta (Northeastern of Italy). The real-time coastline obtained from the GNSS data was validated using the topographic total station measurements; the correspondent polylines obtained from the photogrammetric data (using both automatic extraction and manual restitutions by visual inspection of orhophotos) were compared with the GNSS data to evaluate the performances of the different techniques. The results provided good agreement between the real-time coastlines obtained from different approaches. However, using the optical images, the accuracy was strictly connected with the radiometric changes in the photos and using thermal images, both manual and automatic polylines provided differences in the order of 1–2 m. Multi-temporal comparison of the 0-level coastline with those obtained from a LiDAR survey performed in 2018 provided the detection of the erosion and accretion areas in the period 2018–2022. The investigation on the two case studies showed a better accuracy of the GNSS RTK method in the real-time coastline detection. It can be considered as reliable ground-truth reference for the evaluation of the photogrammetric coastlines. While GNSS RTK proved to be more productive and efficient, optical and thermal SfM provided better results in terms of morphological completeness of the data.

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“…subsidence trends is required to inform coastal sustainability and disaster management actions. Interferometric Synthetic Aperture Radar (InSAR) is a powerful remote sensing technique for measuring relative surface elevation change [7], [8], which can be combined with reliable independent GNSS measurements to obtain absolute measurements in a geodetic reference frame (e.g., [9]- [12]). Leveraging this technology for vertical land motion (VLM) measurements in at-risk areas is an attractive option given the availability of free and open InSAR data with near-global coverage from current and planned Earth observing missions of the European Space Agency (ESA) [13], [14] and NASA/ISRO (U.S. National Aeronautics and Space Administration / Indian Space Research Organisation) [15].…”

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confidence: 99%

Optimized GNSS Cal/Val Site Selection for Expanding InSAR Viability in Areas With Low Phase Coherence: A Case Study for Southern Louisiana

Varugu,

Jones,

Wang

et al. 2024

IEEE J. Sel. Top. Appl. Earth Observations Remote Sensing

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Interferometric Synthetic Aperture Radar (InSAR) techniques can be used to derive spatially dense "relative" measurements of vertical land motion (VLM), whereas Global Navigation Satellite System (GNSS) provides point-based "absolute" measurements of VLM. The combination of GNSS and InSAR observations can yield spatially dense VLM measurements in an absolute reference frame. Additionally, GNSS observations can be used to correct atmospheric noise in InSAR deformation measurements, and serve as a complementary measure to isolate deep and shallow subsidence components. Given the increasing spatial and temporal coverage available from InSAR satellites, there is a need to establish calibration/validation (cal/val) networks that enable use of InSAR for measuring VLM in coherence-challenged areas such as many low-lying coastal lands. In this study, we provide a method for selection of sites for new GNSS installations such that the resulting GNSS network can better serve as tie points and validation for InSAR in areas where low coherence prevents high-fidelity phase unwrapping. Our method is applied in a case study for expanding the existing GNSS network in southern Louisiana, using abandoned oil well sites as potential sites. Considering practical limitations, distribution among various land classes, and following National Geodetic Survey guidelines, our proposed GNSS network consists of 61 (45 existing + 16 new) stations spread over a 50000 km 2 area of southern Louisiana.

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An Integrated InSAR and GNSS Approach to Monitor Land Subsidence in the Po River Delta (Italy)

Cited by 14 publications

References 54 publications

A Statistical Approach for the Integration of Multi-Temporal InSAR and GNSS-PPP Ground Deformation Measurements

A Statistical Approach for the Integration of Multi-Temporal InSAR and GNSS-PPP Ground Deformation Measurements

High-Resolution Real-Time Coastline Detection Using GNSS RTK, Optical, and Thermal SfM Photogrammetric Data in the Po River Delta, Italy

Optimized GNSS Cal/Val Site Selection for Expanding InSAR Viability in Areas With Low Phase Coherence: A Case Study for Southern Louisiana

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