Surface water bodies, such as rivers, lakes, and reservoirs, play an irreplaceable role in global ecosystems and climate systems. Sentinel-2 imagery provides new high-resolution satellite remote sensing data. Based on the analysis of the spectral characteristics of the Sentinel-2 satellite, a novel water index called the Sentinel-2 water index (SWI) that is based on the vegetation-sensitive red-edge band (Band 5) and shortwave infrared (Band 11) bands was developed. Four representative water body types, namely, Taihu Lake, Yangtze River, Chaka Salt Lake, and Chain Lake, were selected as study areas to conduct a water body extraction performance comparison with the normalized difference water index (NDWI). We found that (1) the contrast value of the SWI was larger than that of the NDWI in terms of various water body types, including purer water, turbid water, salt water, and floating ice, which suggested that the SWI could achieve better enhancement performance for water bodies. An (2) effective water body extraction method was proposed by integrating the SWI and Otsu algorithm, which could accurately extract various water body types with high overall accuracy. The (3) method effectively extracted large water bodies and wide river channels by suppressing shadow noise in urban areas. Our results suggested that the novel method can achieve efficient water body extraction for rapidly and accurately extracting various water bodies from Sentinel-2 data and the novel method has application potential for larger-scale surface water mapping.

中文翻译：

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一种有效的水体提取方法，用于 Sentinel-2 图像的新水指数

河流、湖泊和水库等地表水体在全球生态系统和气候系统中发挥着不可替代的作用。Sentinel-2 影像提供了新的高分辨率卫星遥感数据。基于对Sentinel-2卫星光谱特征的分析，基于植被敏感红边波段（Band 5）和短波红外（Band 11) 开发了乐队。选取太湖、长江、茶卡盐湖和链湖4个代表性水体类型作为研究区，与归一化差异水指数（NDWI）进行水体提取性能比较。我们发现 (1) SWI 的对比值大于 NDWI 的各种水体类型，包括较纯的水，浑水、盐水和浮冰，这表明 SWI 可以对水体实现更好的增强性能。(2)将SWI算法与Otsu算法相结合，提出了一种有效的水体提取方法，能够准确提取各种水体类型，整体精度高。(3)方法通过抑制城市区域的阴影噪声，有效地提取了大水体和宽阔的河道。我们的研究结果表明，该新方法可以实现高效的水体提取，可快速准确地从 Sentinel-2 数据中提取各种水体，并且该方法在更大规模地表水测绘方面具有应用潜力。(2)将SWI算法与Otsu算法相结合，提出了一种有效的水体提取方法，能够准确提取各种水体类型，整体精度高。(3)方法通过抑制城市区域的阴影噪声，有效地提取了大水体和宽阔的河道。我们的研究结果表明，该新方法可以实现高效的水体提取，可以快速准确地从 Sentinel-2 数据中提取各种水体，并且该新方法在更大规模地表水测绘方面具有应用潜力。(2)将SWI算法与Otsu算法相结合，提出了一种有效的水体提取方法，能够准确提取各种水体类型，整体精度高。(3)方法通过抑制城市区域的阴影噪声，有效地提取了大水体和宽河道。我们的研究结果表明，该新方法可以实现高效的水体提取，可快速准确地从 Sentinel-2 数据中提取各种水体，并且该方法在更大规模地表水测绘方面具有应用潜力。