Mohammadi Ayub, Karimzadeh Sadra, Jalal Shazad Jamal, Kamran Khalil Valizadeh, Shahabi Himan, Homayouni Saeid, Al-Ansari Nadhir
Department of Remote Sensing and GIS, University of Tabriz, Tabriz 5166616471, Iran.
Institute of Environment, University of Tabriz, Tabriz 5166616471, Iran.
Sensors (Basel). 2020 Dec 16;20(24):7214. doi: 10.3390/s20247214.
Digital elevation model (DEM) plays a vital role in hydrological modelling and environmental studies. Many essential layers can be extracted from this land surface information, including slope, aspect, rivers, and curvature. Therefore, DEM quality and accuracy will affect the extracted features and the whole process of modeling. Despite freely available DEMs from various sources, many researchers generate this information for their areas from various observations. Sentinal-1 synthetic aperture radar (SAR) images are among the best Earth observations for DEM generation thanks to their availabilities, high-resolution, and C-band sensitivity to surface structure. This paper presents a comparative study, from a hydrological point of view, on the quality and reliability of the DEMs generated from Sentinel-1 data and DEMs from other sources such as AIRSAR, ALOS-PALSAR, TanDEM-X, and SRTM. To this end, pair of Sentinel-1 data were acquired and processed using the SAR interferometry technique to produce a DEM for two different study areas of a part of the Cameron Highlands, Pahang, Malaysia, a part of Sanandaj, Iran. Based on the estimated linear regression and standard errors, generating DEM from Sentinel-1 did not yield promising results. The river streams for all DEMs were extracted using geospatial analysis tool in a geographic information system (GIS) environment. The results indicated that because of the higher spatial resolution (compared to SRTM and TanDEM-X), more stream orders were delineated from AIRSAR and Sentinel-1 DEMs. Due to the shorter perpendicular baseline, the phase decorrelation in the created DEM resulted in a lot of noise. At the same time, results from ground control points (GCPs) showed that the created DEM from Sentinel-1 is not promising. Therefore, other DEMs' performance, such as 90-meters' TanDEM-X and 30-meters' SRTM, are better than Sentinel-1 DEM (with a better spatial resolution).
数字高程模型（DEM）在水文建模和环境研究中起着至关重要的作用。从这种地表信息中可以提取许多重要图层，包括坡度、坡向、河流和曲率。因此，DEM的质量和精度会影响提取的特征以及整个建模过程。尽管有来自各种来源的免费DEM，但许多研究人员通过各种观测为其所在区域生成此信息。哨兵 - 1合成孔径雷达（SAR）图像因其可用性、高分辨率以及C波段对地表结构的敏感性，是生成DEM的最佳地球观测数据之一。本文从水文角度对由哨兵 - 1数据生成的DEM与来自其他来源（如AIRSAR、ALOS - PALSAR、TanDEM - X和SRTM）的DEM的质量和可靠性进行了比较研究。为此，获取了一对哨兵 - 1数据，并使用SAR干涉测量技术进行处理，以生成马来西亚彭亨州金马仑高原一部分和伊朗萨南达杰一部分这两个不同研究区域的DEM。基于估计的线性回归和标准误差，由哨兵 - 1生成DEM并未产生理想结果。在地理信息系统（GIS）环境中，使用地理空间分析工具提取了所有DEM的河流。结果表明，由于（与SRTM和TanDEM - X相比）空间分辨率更高，从AIRSAR和哨兵 - 1 DEM中划分出了更多的河流等级。由于垂直基线较短，创建的DEM中的相位去相关导致了大量噪声。同时，地面控制点（GCP）的结果表明，由哨兵 - 1创建的DEM并不理想。因此，其他DEM（如90米分辨率的TanDEM - X和30米分辨率的SRTM）的性能优于哨兵 - 1 DEM（具有更好的空间分辨率）。
