Closson, Abou Karaki, al-Fugha SPACE BORNE RADAR INTERFEROMETRIC MAPPING OF PRECURSORY DEFORMATIONS OF A DYKE COLLAPSE, DEAD SEA, JORDAN Closson, Abou Karaki, al-Fugha dclosson@mail.com naj@paris.com

1650m The case study : the collapse of the salt evaporation pond 19 Ikonos : 19-10-2000 The case study : the collapse of the salt evaporation pond 19 of the Arab poatsh Company 1650m

The SEP costed 32 M Jordan Dinar It collapsed on March 22, 2000 55 M m3 brine to the Dead Sea in less than one our

After the mid sixties The Dead Sea Decrease from -392m To -418m

June, 30 1993 ERS Radar Images May, 29 1999 Lisan Coastline 1961-1962 1993 1999

SAR-based remote sensing technique

Remote sensing SAR SAR = Synthetic Aperture RADAR (RAdio Detection And Ranging) SAR is a sensor able to generate high resolution images imaging sensor:  Allows the observation of the Earth surface in 2D exemple of another sensor : Radar altimetre: provide data in one dimension. Allow generation of topographic maps

SAR remote sensing - properties main characteristics of SAR images: 1. It is an active system (illuminate the area of interest with microwaves)   independant of solar illumination allows measurement in day and night conditions 2. use micro-waves to penetrate through cloud cover   allows observations in cloud cover areas remark: it alters the accuracy of measurements 3. Its a coherent system by opposition to visible remote sensing wich use the incoherent light of the sun  allows the use of interferometry technic Main characteristics of a SAR system 1. Is an active system (it provides its own illumination)   Is not dependent on the sunlight Permits continuous day/night operation 2. Uses microwaves, which have reduced impact of cloud, fog and rain   Permits all-weather imaging Nota: hay un impacto en la fase del SAR 3. It is a coherent system, which provides both the amplitude and the phase of the radar signal  Interferometric techniques can be employed to exploit the information contained in the phase (tema principal del curso)

SAR remote sensing - properties 4. SAR allows the observation of Earth surface properties that are not accessible to visible sensors - rugosity, dielectric properties (through coherence images) - possibilities to penetrate - the vegetation (L band) - ultra dry soil - snow cap 5. The Sar resolution is independant of the distance between the sensor and the objective 6. – Allows the utilisation of different polarization in transmission as well as in reception : HH, HV, VV, VH - Allows the utilization of different frequencies

SAR applications 1. Geometric applications, based on the interferometric phase: - Generation of digital terrain model (DTM) Technic: SAR interferometry (InSAR) - Control the deformations fields over the Earth surface Technic: differential SAR interferometry (DInSAR) 2. Thematic application - Change detection from coherence variation through time (soil erosion, flood)

Deformation fields : principle

DInSAR Topo topographic phase Mov movement Atm atmosphere Noise noise of instruments The differential interferometric phase is a sum of several components

Subidence from 1995-1997