الفهرس 
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Abstract
Coastal areas in many parts of Egypt have undergone a continuous urban expansion due to the growth of cities and improvement of new residential areas. The low elevation and the flate relief of the Nile Delta make a large number of coastal communities particularly which are close to the coastal margin are very sensitive to land subsidence and sea level rising (Becker and Sultan 2009; El-Nahry and Doluschitz 2010; El-Asmar, Hereher et al. 2012; Stanley and Corwin 2012). The transgression of the sea, because of subsidence and sea level rise particularly in vulnerable coastal areas, may result serious problems and has a significant impact on the economy, environment and Society.
Thus, great care should be given to evaluate the land subsidence rates and update the maps of the delta coastline and cities especially in the eastern side of Nile Delta in order to provide decision makers with useful information for integrated development and sustainable use of the land.
Numerous studies have recorded the vertical subsidence velocities on the Nile Delta by using in situ observations (Marriner et al., 2012; Mohamed et al., 2014; Stanley and Warne, 1993; Stanley and Corwin, 2012; Stanley and Toscano, 2009) as well as remote sensing techniques (Aly et al., 2009; Aly et al., 2012; Becker and Sultan, 2009; Bouali, 2013; Frihy, 1988; Fugate, 2014; Poscolieri et al., 2011; Zaid et al., 2014).
Port Said City which is considered one of the most important costal city in Egypt and located at north eastern side of the Nile Delta was chosen to estimate the land subsidence rates and evaluate its hazard in relationship with the sea-level rise. Until now, no precise geodetic measurements have been conducted within Port-Said City to capture the present-day subsidence using the new interferometry SAR method. Port-Said is closely connected with the coast as well as great part of the population and the model of economic and social improvement are found to make it the third largest urban governorate in Egypt (Khaled et al., 2014). Thus, this study aims at determining the modern rates of the land subsidence in Port-Said City using radar interferometry and persistent scatterer techniques and assimilates these recent results with previous ones, in oreder to provide the decision makers in Port-Said Governorate with useful information for sustainable development and land-use planning.
Synthetic Aperture Radar (SAR) is a microwave imaging system which is working regardless of illumination source and weather condition. Radar differential interferometry technique is widely used to measure surface small-scale displacements during the time interval between consecutive radar observations. This technique is based on the information about phase difference of the echo signals recorded by single antenna of the SAR system in the repeated orbits (passes) observations of areas of interest. The subtraction of digital elevation model phase in the differential radar interferometry (DInSAR) provides us with the variations of the signal path length between the observations which including displacements of scattering surface. DInSAR technique provides a detailed map of the radial displacements of scattering surface elements, so it used worldwide for a wide applications such as land subsidence, mapping terrain heights and monitoring active volcanoes, active tectonics, landslides, and earthquake activities, as well as studying glacier dynamics.
In the last few years a number of synthetic aperture radar (SAR) space-borne satellites have been deployed in orbits. They operate in different wavelengths such as L-band (23 cm – 1.30GHz and 24 cm – 1.25 GHz), C-band (6 cm – 5.0 GHz), and X-band (3 cm – 10 GHz). In addition, the diversity of SAR sensors expands DInSAR capabilities towards a more complete characterization of the motion information of the studied area. In this thesis, L-band microwave SAR images acquired by ALOS/PALSAR were used to estimate the land subsidence rate of Port-Said City. ALOS/PALSAR is an L-band SAR which was launched in June 2006 by Japanese Aerospace Agency (JAXA). InSAR/DInSAR can be analyzed every 46 days due to the ALOS orbit revisit time. PALSAR is a fully polarimetric instrument operating in fine-beam mode with single polarization (HH or VV), dual polarization (HH+HV or VV+VH), and full polarimetry (HH+HV+VH+VV). The center frequency is 1.27 GHz. (24 cm.) with incidence angle ranges 7.9°-60.0°. In this research work the ALOS PALSAR data of only fine beam single (FBS) mode and with short temporal baseline were used.
Differential synthetic aperture radar interferometry (DInSAR) technique provides a perfect detailed map of the radial displacements of scattering surface elements with respect to radar in contrast with individual profiles or point measurements provided typically in field measurements (Berardino et al., 2002; Colesanti et al., 2001; Galloway et al., 1998; Mora et al., 2003). DInSAR is not only so accurate technique suitable for measuring deformation in land, but also less expensive and quicker than the conventional ground-based survey methods such as Differential Global Positioning System (DGPS) and instrumental methods. However, these tools provide point measurements that are spatially and/or temporally limited. Moreover, DInSAR have already proven their efficiency for monitoring ground deformation in many applications due to their high precision and high spatial resolution (Carnec et al., 1996; Chang et al., 2005; Ng et al., 2012; Poscolieri et al., 2011; Smith, 2002; Yhokha et al., 2015).
Thus, in this study, Differential synthetic aperture radar interferometry technique (DInSAR) with its millimeter accuracy was used to monitor the land subsidence rates in Port-Said City of Egypt to obtain precise detection of land deformation of the study area. In order to achieve that objective a perfect DEM should be used, thus the stereo pair of ALOS/PRISM data has been used to generate DEM with 2.5 m spatial resolution.