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Proceedings Paper

Decorrelation mechanisms in C-band SAR interferometry over boreal forest
Author(s): Gary Smith; Patrik B.G. Dammert; Jan Askne
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Paper Abstract

Temporal and spatial decorrelation effects are very important in repeat pass interferometric imaging of boreal forest. Temporal decorrelation refers to changes in the strength and distribution of scattering, due to the effects of wind, rain, and moisture changes of both canopy and ground. Spatial decorrelation is a result of baseline decorrelation, volume scattering, and uncompensated topography. These effects complicate interferometric imaging and the use of interferometry for topographic mapping of forest covered regions. The differences between heights measured from interferograms over forest and a DEM (the effective tree height) are related to the coherence. Another problem is the decrease in accuracy of coherence estimates (e.g. for land use classification) when the coherence is low. Influences of various factors on coherence in interferometry using images from the ERS-1 3 day repeat cycle of 1994 are studied. A wide range of time intervals between images and of baselines is used. The coherence of various surfaces is found to vary considerably between interferograms. As the time interval increases, the coherence generally decreases. The causes of decorrelation and their relation to meteorological effects and volume scattering are investigated. Analysis of coherence over various surfaces in Northern Sweden during the winter of 1994 is performed, with particular emphasis on forest, clear cut and agricultural areas.

Paper Details

Date Published: 17 December 1996
PDF: 11 pages
Proc. SPIE 2958, Microwave Sensing and Synthetic Aperture Radar, (17 December 1996); doi: 10.1117/12.262703
Show Author Affiliations
Gary Smith, Chalmers Univ. of Technology (Sweden)
Patrik B.G. Dammert, Chalmers Univ. of Technology (Sweden)
Jan Askne, Chalmers Univ. of Technology (Sweden)

Published in SPIE Proceedings Vol. 2958:
Microwave Sensing and Synthetic Aperture Radar
Giorgio Franceschetti; Christopher John Oliver; Franco S. Rubertone; Shahram Tajbakhsh, Editor(s)

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