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Proceedings Paper

Tropospheric delay signal in SAR interferogram and its correction for precise surface change detection
Author(s): Satoshi Fujiwara; Makoto Murakami; Mikio Tobita; Hiroyuki Nakagawa; Paul A. Rosen
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Paper Abstract

Synthetic aperture radar (SAR) interferometry has become an important tool for measuring the surface deformation and mapping topography. The largest error source of the SAR interferometry measurements is differential atmospheric delay of water vapor. It reflects detailed distribution of water vapor in troposphere at data acquisition. We found phase difference associated with atmospheric waves and severe local atmospheric phenomena in interferograms. To distinguish phase difference associated with surface deformation from tropospheric effect, we need several SAR interferograms including the time period of the deformation. Averaging the interferograms is an effective way to reduce the tropospheric delay from horizontal inhomogeneity of the water vapor distribution. Apart form the tropospheric delay of the horizontal water vapor inhomogeneity, we often find the differential phase correlated to the topography (elevation) in interferograms, which might cause error in interpretation of surface deformation. This phase is due to the differential tropospheric delay caused by the topography and vertical change of water vapor between two images in different atmospheric condition. Theoretical calculation shows that the phase difference can be approximated by linear expression of the elevation. We applied a simple and effective correction method that the error is removed by subtracting the DEM multiplied a coefficient.

Paper Details

Date Published: 21 December 2000
PDF: 8 pages
Proc. SPIE 4152, Microwave Remote Sensing of the Atmosphere and Environment II, (21 December 2000); doi: 10.1117/12.410597
Show Author Affiliations
Satoshi Fujiwara, Geographical Survey Institute (Japan)
Makoto Murakami, Geographical Survey Institute (Japan)
Mikio Tobita, Geographical Survey Institute (Japan)
Hiroyuki Nakagawa, Geographical Survey Institute (Japan)
Paul A. Rosen, Jet Propulsion Lab. (United States)


Published in SPIE Proceedings Vol. 4152:
Microwave Remote Sensing of the Atmosphere and Environment II
Thomas T. Wilheit; Harunobu Masuko; Hiroyuki Wakabayashi, Editor(s)

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