基于高分影像的城市黑臭水体遥感识别方法研究
Research on Remote Sensing Identification Methods of Urban Black and Odorous Water Bodies with Gaofen Images
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摘要: 城市黑臭水体是一种极端的水污染现象, 威胁人类的生产生活和水生态环境健康. 利用遥感手段及时、准确地识别黑臭水体的时空分布, 对掌握黑臭水体治理进展、推进水污染控制管理起着重要作用. 以广州市为研究区域, 基于黑臭水体和正常水体在高分影像上的光谱差异, 构建了多个黑臭水体识别模型, 并采用了一种自动阈值选取算法进行模型阈值的快速选取, 进而进行了城市黑臭水体的遥感识别, 探讨了影响识别精度的因素. 研究结果表明, 采用构建的模型识别黑臭水体总体精度最高可达96.8%; 从黑臭水体识别的空间分布来看, 该模型错分率较小, 尤其在细小河涌中有较好的识别效果; 地表水质数据和卫星影像的一致性误差、高分影像融合方法和混合像元的存在等可能是导致模型错误识别黑臭水体的原因. 基于高分影像的黑臭水体识别模型和自动阈值选择方法可实现对城市黑臭水体的快速和高效识别, 为黑臭水体治理和城市水环境精细管理提供有效支撑.Abstract: Urban black and odorous water (BOW) bodies are extreme water pollution phenomena that threaten human production, life, and the health of aquatic ecosystems. Timely and accurate identification of the spatial and temporal distribution of BOW using remote sensing techniques plays a crucial role in understanding the progress of their treatment and advancing water pollution control and management. In this study, taking Guangzhou City as the study area, several BOW identification models were constructed based on the spectral differences between BOW and normal water in Gaofen (GF) image with high spatial resolution. Then an automatic threshold selection algorithm was employed for rapid threshold selection in the BOW models, enabling the detection of BOW bodies. The results showed that the overall identification accuracy of BOW bodies could reach up to 96.8%. In terms of the spatial distribution of BOW identification, the constructed model e1 had a relatively low misclassification probability and achieved good recognition performance, especially in small rivers and streams. The errors in consistency between surface water quality data and satellite images, high-resolution image fusion methods, and the existence of mixed pixels may be the causes of misidentification for BOW. The BOW model based on high spatial resolution images with automatic threshold selection can achieve fast and efficient detection of BOW bodies, providing effective support for BOW treatment and the precise management of the urban water environment.