A Multi-Sensor Comparative Analysis on the Suitability of Generated DEM from Sentinel-1 SAR Interferometry Using
Ayub Mohammadi1, Sadra Karimzadeh1,2,3, Shazad Jamal Jalal4,5
1Department of Remote Sensing and GIS, University of Tabriz, Tabriz 5166616471, Iran.
Sensors (Basel, Switzerland)
|December 19, 2020
Summary
Digital elevation models (DEMs) are crucial for environmental studies. DEMs generated from Sentinel-1 SAR data showed noise and inaccuracies, performing worse than SRTM and TanDEM-X for hydrological applications.
Area of Science:
- Geosciences
- Remote Sensing
- Hydrology
Background:
- Digital Elevation Models (DEMs) are fundamental for hydrological and environmental studies, influencing extracted features like slope, aspect, and river networks.
- The quality and accuracy of DEMs directly impact the reliability of geospatial analysis and modeling.
- Sentinel-1 synthetic aperture radar (SAR) data offers high-resolution, C-band imagery suitable for DEM generation, prompting investigation into its utility.
Purpose of the Study:
- To conduct a comparative hydrological analysis of DEMs derived from Sentinel-1 data against those from AIRSAR, ALOS-PALSAR, TanDEM-X, and SRTM.
- To evaluate the quality and reliability of Sentinel-1 derived DEMs for hydrological applications.
- To assess the performance of Sentinel-1 DEMs in delineating river streams and compare it with other DEM sources.
Main Methods:
- Sentinel-1 SAR data pairs were acquired and processed using SAR interferometry to generate DEMs for two distinct study areas.
- Geospatial analysis tools within a GIS environment were employed to extract river streams from all generated and existing DEMs.
- Performance was evaluated using linear regression, standard errors, spatial resolution comparison, and analysis of ground control points (GCPs).
Main Results:
- DEMs generated from Sentinel-1 data exhibited significant noise due to phase decorrelation, attributed to a shorter perpendicular baseline.
- Despite Sentinel-1's higher spatial resolution, which led to the delineation of more stream orders compared to SRTM and TanDEM-X, its overall accuracy was compromised.
- Ground control point analysis indicated that Sentinel-1 derived DEMs were not promising, with DEMs like SRTM (30m) and TanDEM-X (90m) demonstrating superior performance.
Conclusions:
- DEM generation from Sentinel-1 data using SAR interferometry, while offering high spatial resolution, yielded results with considerable noise and lower reliability for hydrological applications.
- Existing DEMs such as SRTM and TanDEM-X, despite potentially lower spatial resolution, provided more reliable hydrological information than the Sentinel-1 derived DEMs in the study areas.
- Further research may be needed to optimize Sentinel-1 data processing techniques for improved DEM quality in hydrological modeling.
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