Paris       Barcelona       Las Vegas     Munich       Delft       MERIS instrument

To obtain the results the available ERS and ASAR datasets from 1995 to 2004 have been input to the processing chain to obtain both, the linear term of the subsidence displacement and the temporal evolution of the position of the targets. A very precise positioning of the pixel in the line of sight (namely DEM error) is as well derived. using high perpendicular baselines.

The following figures show the linear subsidence and the DEM error obtained on the validation area. The subsidence maps show good agreement with the well-known upsidence around the work construction of the Gare St Lazare and the subsidence around the area of the Grand Palais. Profiles were obtained for all the points showing a good model coherence in this area and used for the comparison with the optical leveling. The profile on one of the points in from of the station is shown in figure 2.



Figure 1: Subsidence map covering the period 1995- 2001 for the area of validation. Plot shows all those point with a high model coherence.



Figure 2: Temporal profile of a point located in front of the St Lazare station as a function of number of observations (marked with a circle in Figure 1). No discontinuity can be noticed between the ERS and ENVISAT acquisitions.



Figure 3: DEM error derived on points showing a high model coherence for the area of validation.

................................

The following figure shows the lineal subsidence component geocoded over a cartographic map. For this procedure the correction in their position given by the precise altitude determination has been incorporated. It can be clearly seen how the stable scatterers align with the different man-made structures such as the Grand Palais building and the different streets in the southern part of the Seine river.



Figure 4: Geocoded subsidence map on the area of the Grand Palais


The test site of Paris was also processed with an independent interferometric processing chain from the DLR. Results show good agreement with the previous ones derived from the Altamira Information processor.



Figure 5: Estimated linear displacement rates for points showing a high model coherence. Red corresponds to 5 mm/year subsidence, blue to 5 mm/year uplift.