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Large-scale deformation of Tibet measured with Envisat ScanSAR interferometry

Eric Fielding(1), Paul Rosen(1) and Roland Burgmann(2)

(1) Jet Propulsion Lab, Caltech, 4800 Oak Grove Drive, Pasadena, California 91109, United States
(2) University of California, Berkeley, McCone Hall, Berkeley, California 94720, United States


Scanning synthetic aperture radar (ScanSAR) interferometry has the potential to map deformation over large areas. The large actively deforming area and arid climate of Tibet make it an excellent test area for the ScanSAR interferometry technique, which has been proposed as a possible SAR operation mode for the DESDynI mission recommended by the Decadal Survey. The Envisat Wide Swath (WS) mode was not originally designed for interferometry, but at least one in five pairs had the required burst synchronization before January 2007, when the European Space Agency began attempting to greatly improve the burst synchronization and reduce the variation in baselines. Unfortunately, some of the WS data over Tibet has been acquired in HH polarization and some in VV polarization, causing an additional limitation on usable interferometric pairs. Several Envisat tracks across Tibet have appropriate WS acquisitions to form interferometric pairs. Initial results show a reduction of coherence in eastern Tibet where the plateau climate is wetter and allows more vegetation cover. Processing long strips (>1000 km) with the full WS width gives strong constraints on the baseline between the two orbits of image-pair acquisitions and enables better separation of atmospheric effects and orbit errors from moderate-wavelength (~100 km) deformation signals. Long-wavelength control from GPS or other ground-based data is still required for the longest wavelengths (>300 km).


Workshop presentation

Keywords: ESA European Space Agency - Agence spatiale europeenne, observation de la terre, earth observation, satellite remote sensing, teledetection, geophysique, altimetrie, radar, chimique atmospherique, geophysics, altimetry, radar, atmospheric chemistry