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Publicações

Publicações por Joaquim João Sousa

2016

Potential of C-Band SAR Interferometry for Dam Monitoring

Autores
Sousa, JJ; Ruiz, AM; Bakon, M; Lazecky, M; Hlavacova, I; Patricio, G; Manuel Delgado, JM; Perissin, D;

Publicação
INTERNATIONAL CONFERENCE ON ENTERPRISE INFORMATION SYSTEMS/INTERNATIONAL CONFERENCE ON PROJECT MANAGEMENT/INTERNATIONAL CONFERENCE ON HEALTH AND SOCIAL CARE INFORMATION SYSTEMS AND TECHNOLOGIES, CENTERIS/PROJMAN / HCIST 2016

Abstract
Despite the recent popularity achieved by the modern X-band SAR sensors, mainly due to their high spatial resolutions which enable the detection of deformation components impossible so far, such as thermal expansion, SAR C-band sensors continue to be of great utility and with a great future in the deformation monitoring field, namely for critical structure monitoring, such as dams. The new ESA missions (Sentinel-1A and 1B) and the extension of the Canadian Radarsat mission corroborate this finding. In this paper the possibility of using spacebome SAR sensors for dam monitoring is addressed in terms of feasibility and applications. The presented results show the potential of C-band sensors for the particular case of dam monitoring and can be handful to recognize the applicability of new Sentinel-1 data (since 2014) for continuous monitoring of dam deformations. (C) 2016 The Authors. Published by Elsevier B.V.

2016

Subsidence monitoring in the coastal region of Nigeria using multi temporal interferometric synthetic aperture radar (MT-Insar)

Autores
Mahmud, MU; Yakubu, TA; Adewuyi, TO; Sousa, JJ; Ruiz Armenteros, AM; Bakon, M; Lazecky, M; Perissin, D;

Publicação
European Space Agency, (Special Publication) ESA SP

Abstract
The uncontrolled exploitation of the groundwater, oil and gas in the Nigerian coastal geosyncline has led to progressive decline of the aquifer level and a continuous need for opening deeper drillings to exploit deeper aquifers. From the analysis of the interferometric results derived from the application of Multi-Temporal Interferometry (MT-InSAR) technique, Lagos state appears to be subsiding conically up to -7 mm/yr. The velocity rates of subsidence in the surrounding cities like Lekki, Badagry, Ikorodu and Epe are much higher than in Lagos city. These preliminary investigation results reveal heavy structures, in particular buildings, that were seen constructed mostly on the sand filled areas where the sediments compaction rates is very high.

2017

Bridge Displacements Monitoring Using Space-Borne X-Band SAR Interferometry

Autores
Lazecky, M; Hlavacova, I; Bakon, M; Sousa, JJ; Perissin, D; Patricio, G;

Publicação
IEEE JOURNAL OF SELECTED TOPICS IN APPLIED EARTH OBSERVATIONS AND REMOTE SENSING

Abstract
The development of interferometric methodologies for deformation monitoring that are able to deal with long time series of synthetic aperture radar (SAR) images made the detection of seasonal effects possible by decomposing the differential SAR phase. In the case of monitoring of man-made structures, particularly bridges, the use of high-resolution X-band SAR data allows the determination of three major components with significant influence on the SAR phase: the linear deformation trend, the height of structures over terrain, and the thermal expansion. In the case of stable metallic or (reinforced) concrete structures, this last effect can reach a magnitude comparable to or even exceeding the other phase components. In this review, we present two case studies that confirm the feasibility of InSAR techniques for bridge deformation monitoring and our original approach to refine the thermal expansion component.

2016

Concept Of An Effective Sentinel-1 Satellite SAR Interferometry System

Autores
Lazecky, M; Comut, FC; Bakon, M; Qin, Y; Perissin, D; Hatton, E; Spaans, K; Mendez, PJG; Guimaraes, P; de Sousa, JJM; Kocich, D; Ustun, A;

Publicação
INTERNATIONAL CONFERENCE ON ENTERPRISE INFORMATION SYSTEMS/INTERNATIONAL CONFERENCE ON PROJECT MANAGEMENT/INTERNATIONAL CONFERENCE ON HEALTH AND SOCIAL CARE INFORMATION SYSTEMS AND TECHNOLOGIES, CENTERIS/PROJMAN / HCIST 2016

Abstract
This brief study introduces a partially working concept being developed at IT4Innovations supercomputer (HPC) facility. This concept consists of several modules that form a whole body of an efficient system for observation of terrain or objects displacements using satellite SAR interferometry (InSAR). A metadata database helps to locate data stored in various storages and to perform basic analyzes. A special database has been designed to describe Sentinel-1 data, on its burst level. Custom Sentinel-1 TOPS processing algorithms allow an injection of coregistered bursts into the database. Once the area of interest is set and basic processing parameters are given, the selected data are merged and processed by the Persistent Scatterers (PS) InSAR method or an optimized Small Baselines (SB) InSAR derivative. Depending on the expected deliverables, the processing results can be post-analyzed using a custom approach, in order to achieve a set of reliable measurement points. Final results can be post processed and visualized using a custom GIS toolbox, consisting in open-source GIS functionality. The GIS post-processing is enforced by HPC power as well. To demonstrate the practical applicability of the described system, a subsidence area in Konya city, Turkey is used as the study area for Sentinel-1 InSAR evaluation. (C) 2016 The Authors. Published by Elsevier B.V.

2017

Factors determining subsidence in urbanized floodplains: evidence from MT-InSAR in Seville (southern Spain)

Autores
Ruiz Constan, A; Ruiz Armenteros, AM; Galindo Zaldivar, J; Lamas Fernandez, F; Sousa, JJ; Sanz de Galdeano, CS; Pedrera, A; Martos Rosillo, S; Cuenca, MC; Manuel Delgado, JM; Hanssen, RF; Gil, AJ;

Publicação
EARTH SURFACE PROCESSES AND LANDFORMS

Abstract
Major rivers have traditionally been linked with important human settlements throughout history. The growth of cities over recent river deposits makes necessary the use of multidisciplinary approaches to characterize the evolution of drainage networks in urbanized areas. Since under-consolidated fluvial sediments are especially sensitive to compaction, their spatial distribution, thickness, and mechanical behavior must be studied. Here, we report on subsidence in the city of Seville (Southern Spain) between 2003 and 2010, through the analysis of the results obtained with the Multi-Temporal InSAR (MT-InSAR) technique. In addition, the temporal evolution of the subsidence is correlated with the rainfall, the river water column and the piezometric level. Finally, we characterize the geotechnical parameters of the fluvial sediments and calculate the theoretical settlement in the most representative sectors. Deformation maps clearly indicate that the spatial extent of subsidence is controlled by the distribution of under-consolidated fine-grained fluvial sediments at heights comprised in the range of river level variation. This is clearly evident at the western margin of the river and the surroundings of its tributaries, and differs from rainfall results as consequence of the anthropic regulation of the river. On the other hand, this influence is not detected at the eastern margin due to the shallow presence of coarse-grain consolidated sediments of different terrace levels. The derived results prove valuable for implementing urban planning strategies, and the InSAR technique can therefore be considered as a complementary tool to help unravel the subsidence tendency of cities located over under-consolidated fluvial deposits. Copyright (c) 2017 John Wiley & Sons, Ltd.

2015

Deformation monitoring in Zafarraya fault and Sierra Tejeda antiform (Betic cordillera, Spain) using satellite radar interferometry

Autores
Ruiz Armenteros, AM; Delgado, JM; Sousa, JJ; Hanssen, RF; Caro, M; Gil, AJ; Galindo Zaldívar, J; De Galdeano, CS;

Publicação
European Space Agency, (Special Publication) ESA SP

Abstract
The Betic-Rif cordilleras are build-up in the western Mediterranean by the deformations related to the Eurasian-African plate boundary. The recent NW-SE convergence produces the simultaneous development of large folds and faults in the central part of the Internal Zones of the Betic Cordilleras, which continues active up to Present. The uplift of the mountain ranges is mainly related to the development of folds in this regional compressive setting. Sierra Tejeda constitutes a relief related to the development of a complex shaped recent antiform that is located near the coast line. At the northern limb of Sierra Tejeda is located the Zafarraya fault, a high-angle northwards dipping normal fault. Understanding the tectonic of the Zafarraya fault is crucial since one of the most destructive earthquakes (25th December 1884) on the Iberian Peninsula occurred along this fault (magnitude of 6.7). This paper investigates the applicability of satellite radar interferometry using ERS-1/2 SAR and Envisat ASAR datasets to help to constraint the geological hazard in this part of the Betic Cordillera.

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