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Tropospheric correction techniques in repeat-pass SAR interferometry

Li, Z; Muller, JP; Cross, P; (2004) Tropospheric correction techniques in repeat-pass SAR interferometry. In: (pp. pp. 327-332).

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Abstract

For the first time, the application of a spaceborne near infrared (IR) water vapour product from the NASA Moderate Resolution Imaging Spectroradiometer (MODIS) for reducing water vapour effects of ERS-2 measurements are presented. The MODIS near IR water vapour product has been available since the end of February 2000 with a spatial resolution of 1km (at nadir) and a moderate accuracy of 5-10%. Coincident data with ERS-2 used in this study were located over Mt. Etna and Southern California. The results showed that the MODIS near IR water vapour product could be useful in reducing atmospheric effects in ERS-2 SAR interferometric data. Taking these results into account and the fact that, the MEdium Resolution Imaging Spectrometer (MERIS) has a higher accuracy and is on board the same platform, ENVISAT, as the Advanced Synthetic Aperture Radar (ASAR), future prospects look optimistic. The major limitation for either MODIS or MERIS is the reliance on cloud-free water vapour retrievals with the percentage of cloud free observations as low as 25%. In this paper, also for the first time, 3D GPS water vapour (or wet refractivity) models were applied to correct ERS-2 SAR interferometric data. Firstly, the WAter Vapour Extraction Software (WAVEs), developed at UCL, was used to construct a 3D water vapour (or wet refractivity) model with an appropriate resolution making full use of the spatial structure of zenith wet delays; then the difference in LOS (Line-of-Sight) path delays were calculated and applied to correct InSAR measurements. The results showed that the volumetric fields derived using the 3D GPS water vapour model can reduce water vapour effects significantly. It also showed that such 3D models are sensitive to the distribution of GPS receivers. Presently, a new way to fuse MODIS or MERIS with ground-based GPS networks within the WAVEs package is under investigation at UCL.

Type: Proceedings paper
Title: Tropospheric correction techniques in repeat-pass SAR interferometry
UCL classification: UCL > Provost and Vice Provost Offices
UCL > Provost and Vice Provost Offices > UCL BEAMS
UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Engineering Science
UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Engineering Science > Dept of Civil, Environ and Geomatic Eng
UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences
UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > Dept of Space and Climate Physics
URI: http://discovery.ucl.ac.uk/id/eprint/189320
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