Wang Hang-Hang, Wang Jie, Cui Yu-Huan
School of Resources and Environmental Engineering, Anhui University, Hefei 230601, China.
Anhui Province Key Laboratory of Wetland Ecosystem Protection and Restoration, Anhui University, Hefei 230601, China.
Huan Jing Ke Xue. 2020 Mar 8;41(3):1207-1216. doi: 10.13227/j.hjkx.201907164.
Carrying out monitoring of suspended sediment concentration in river and lake systems is of great significance for understanding the laws of sediment transport in water and formulating policies on water environmental control. Taking Shengjin Lake and the connected Yangtze river section in Anhui province as the study area, band reflectance of a Sentinel-2 MSI sensor is simulated according to field spectral datasets, and the retrieval model is established by statistical regression from the synchronized suspended sediment concentration measurements. Then, the retrieved results from 28 scene MSI images during 2017-2019 are used to analyze the spatiotemporal variation of suspended sediment concentration in rivers and lakes, and the influence of water level variation on their spatial differentiation is also discussed. The results show that:① The retrieval model established by the ratio of the sixth band to the third band of the MSI sensor is suitable for high-turbidity water type, with high accuracy (=0.863, RMSE=22.211 mg·L). ② Spatially, the suspended sediment concentration near the lake entrances, northwestern parts of the upper and middle lake areas, and the lower lake is relatively higher, and that of Shengjin Lake is lower than that of the Yangtze River overall except for in summer. Temporally, the suspended sediment concentration in Shengjin Lake is relatively lower in summer and higher in other seasons, while the connected Yangtze River section exhibits the opposite intra-annual variation. ③ The water level, which is caused by the connectivity of rivers and lakes under the influence of the sluice, is the key factor affecting the spatial differentiation of suspended sediment concentration in the river and lake system. The suspended sediment concentration in Shengjin Lake contributes to the Yangtze River in dry and normal water periods, and that in the normal water period is more significant. In contrast, during the flood period, the correlation between suspended sediment concentration in the Yangtze River and that in Shengjin Lake is not obvious.
开展河湖水系悬浮泥沙浓度监测对于了解水体泥沙输移规律和制定水环境控制政策具有重要意义。以安徽省升金湖及其相连长江段为研究区域，根据野外光谱数据集模拟哨兵 - 2 多光谱成像仪（MSI）传感器的波段反射率，并通过与同步悬浮泥沙浓度测量值进行统计回归建立反演模型。然后，利用 2017 - 2019 年期间 28 景 MSI 影像的反演结果分析河湖水系悬浮泥沙浓度的时空变化，并探讨水位变化对其空间分异的影响。结果表明：①由 MSI 传感器第六波段与第三波段比值建立的反演模型适用于高浊度水体类型，精度较高（=0.863，均方根误差 =22.211 mg·L）。②空间上，湖口附近、湖体中上部西北区域及湖体下部悬浮泥沙浓度相对较高，除夏季外升金湖总体悬浮泥沙浓度低于长江。时间上，升金湖夏季悬浮泥沙浓度相对较低而其他季节较高，相连长江段年内变化则相反。③受水闸影响，河湖连通引起的水位变化是影响河湖水系悬浮泥沙浓度空间分异的关键因素。枯水期和正常水位期升金湖向长江输沙，正常水位期输沙作用更显著。相反，汛期长江与升金湖悬浮泥沙浓度相关性不明显。
