地理与地理信息科学

在天然水域中，浅滩作为泥沙淤积形成的沉积体，兼具生态保护与人文景观价值，对我国第一大淡水湖湿地——鄱阳湖浅滩湿地开展遥感监测研究能为大尺度湿地资源的精准管理提供决策依据。针对地表水与部分建筑在NDWI影像中容易混淆的问题，本文构建可见光近红外波段的有符号总反射率指数（Signed Total Reflectance Index,STRI），并实现流域地表水提取和地表水覆盖频率（水淹频率）统计，借助面向对象影像分析和数学形态学技术有效剔除细碎水体；通过1986—2022年多年水淹频率的统计分析识别鄱阳湖流域各类浅滩。结果表明，基于STRI时间序列及年水淹频率统计的方法能有效区分不同发育阶段的浅滩类型，鄱阳湖流域浅滩和水域制图将为流域生态治理、航运规划管理、水域环境分析等提供数据支撑。

Shallow sands are sedimentary bodies formed by siltation in natural water bodies.The shallow wetlands in the Poyang Lake Basin,the largest of their kind in China,passes significant ecological and cultural values.Conducting remote sensing monitoring of these shallow sands not only help fulfill understanding their dynamic changes but also provides a scientific basis for the precise management of large-scale wetland resources.Leveraging the Google Earth Engine and Landsat time-series imagery,this study proposes a method for extracting shallow sands and different developmental stages in the Poyang Lake Basin based on inundation frequency statistics.To address the confusion between surface water and some buildings in the normalized difference water index(NDWI),a signed total reflectance index(Signed Total Reflectance Index,STRI) is constructed using visible and near-infrared spectral bands.Based on the STRI,the extraction of surface water and the calculation of surface water coverage frequency(inundation frequency) are achieved.Object-oriented image analysis and mathematical morphology are then employed to effectively eliminate fragmented water bodies.Through the statistical analysis of multi-year inundation frequency from 1986 to 2022,various types of shallow sands in the Poyang Lake Basin are identified.The results demonstrate that the proposed method,based on STRI time series and annual inundation frequency statistics,can effectively classify shallow types at different developmental stages.The resulting maps of shallow sands and water areas in the Poyang Lake Basin provide reliable data support for basin ecological governance,shipping planning and management,water environment analysis,and related fields.