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Impacts of geoid height on large-scale crustal deformation mapping with InSAR observations

Lookup NU author(s): Professor Zhenhong Li


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An ellipsoidal height datum (e.g. WGS84) is required in SAR Interferometric processing, whilst DEMs are often referenced to a geoid datum (e.g. EMG96). Therefore, geoid height error is introduced due to the inconsistency of height datums in InSAR derived displacement maps. In this paper, the relationship between geoid heights and uncertainties in InSAR displacements is investigated using 27 scenes of Envisat ASAR ScanSAR images and 44 scenes of Image-mode images covering the western Altyn Tagh Fault, northern Tibetan Plateau. A typical error of 8.8 m in SRTM DEM leads to 3mm uncertainty in an InSAR interferogram with a perpendicular baseline of 100m, whilst a geoid height of 20m can result in 10mm uncertainty. Geoid height varies from one place to another, and is highly correlated with topography. The impacts of geoid height on InSAR displacements increase with perpendicular baselines, but SAR images with a small perpendicular baseline may not be available in some cases. In addition, it may also not always be feasible to use a best-fitting plane to remove the impacts of geoid height. It is thus highly recommended in this paper that DEMs with an ellipsoidal height datum should be employed in interferometric processing, particularly when long-wavelength crustal deformation is targeted.

Publication metadata

Author(s): Li P, Li Z, Shi C, Feng W, Liang C, Li T, Zeng Q, Liu J

Publication type: Article

Publication status: Published

Journal: Chinese Journal of Geophysics (Chinese Edition)

Year: 2013

Volume: 56

Issue: 6

Pages: 1857-1867

Print publication date: 24/06/2013

ISSN (print): 0898-9591

ISSN (electronic): 2326-0440

Publisher: Zhongguo Diqiu Wuli Xuehui


DOI: 10.6038/cjg20130608


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