Comparing flooded area detection between the hydraulic modelling and Sentinel-1 radar imagery processed by Automatic Detection of Water Bodies (Sentinel-1 ADWB) confirmed that SAR (Synthetic Aperture Radar) imagery shows good potential for improving flood studies. The study was performed in a study area of the Krka River floodplain (Slovenia). The focus was to analyse the overlapping areas between the Sentinel-1 ADWB and numerical hydraulic modelling and to recognise the factors that play a role in the differences between those areas. At the same time, the study also demonstrated the applicability of Sentinel-1 ADWB. The overlapping between the two data sources was up to 66%. The most significant differences between the data were in areas simulated by the hydraulic modelling but not detected by satellite imagery processed by Sentinel-1 ADWB. These were mainly areas with dense vegetation, such as forests, where the satellite (as expected) had difficulty detecting floods, and detection borders, where detection was difficult due to lower water depths and/or detection limitations due to spatial resolution or region growing process. Areas less well modelled by the hydraulic model than satellite imagery were also identified, indicating regions where Sentinel-1 ADWB can improve flood studies as additional data for hydraulic simulation. The study shows that users need to understand the drawbacks and advantages of modes for obtaining the data – radar satellite imagery (problems under dense vegetation, spatial resolution, etc.) and hydraulic model (lack of quality input data, the precipitation directly above the studied area, water inflow from the hinterland, etc.). Based on the knowledge of the areas where Sentinel-1 ADWB data can be useful, the data’s potential for calibration and verification processes of hydraulic studies is suggested.

中文翻译：

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Sentinel-1 影像在洪水事件检测方面的潜力：卫星与水力模型的比较


将水力建模与水体自动检测 （Sentinel-1 ADWB） 处理的 Sentinel-1 雷达图像之间的淹没区域检测进行比较，证实 SAR（合成孔径雷达）图像显示出改进洪水研究的良好潜力。该研究是在 Krka 河洪泛区（斯洛文尼亚）的研究区域进行的。重点是分析 Sentinel-1 ADWB 和数值水力建模之间的重叠区域，并识别在这些区域之间的差异中发挥作用的因素。同时，该研究还证明了 Sentinel-1 ADWB 的适用性。两个数据源之间的重叠高达 66%。数据之间最显着的差异是在水力建模模拟的区域，但 Sentinel-1 ADWB 处理的卫星图像未检测到的区域。这些主要是植被茂密的区域，例如森林，卫星（如预期的那样）难以检测洪水，以及检测边界，由于水深较低和/或由于空间分辨率或区域生长过程而导致检测限制而难以检测。还确定了水力模型建模不如卫星图像更好的区域，表明 Sentinel-1 ADWB 可以作为水力模拟的附加数据改进洪水研究的区域。研究表明，用户需要了解获取数据的方式的优缺点 – 雷达卫星图像 （植被茂密、空间分辨率等下的问题） 和水力模型 （缺乏高质量的输入数据、研究区域正上方的降水、腹地的水流入等）。 基于对 Sentinel-1 ADWB 数据可能有用的领域的了解，提出了该数据在水力研究的校准和验证过程中的潜力。