中文关键词
Sentinel-2 MSI影像升金湖悬浮物浓度遥感反演水位 | 英文关键词Sentinel-2 MSI imageShengjin Lakesuspended sediment concentrationremote sensing retrievalwater level |
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| 中文摘要 |
| 开展河湖系统悬浮物监测对掌握水体泥沙运移规律、制定水环境治理措施具有重要意义.以安徽省升金湖与连接长江段水体为研究区，根据实测光谱模拟Sentinel-2 MSI影像波段反射率，结合同步水体悬浮物实测数据建立反演模型；而后根据2017~2019年28景MSI影像水体悬浮物反演结果，分析河湖系统水体悬浮物浓度的变化规律，并探究水位变化对其空间分异的影响.结果表明：①根据MSI影像第六波段与第三波段的比值建立的二次多项式模型具有较高的反演精度（R2=0.863，RMSE=22.211 mg·L-1），适用于高浊度水体悬浮物反演；②在空间上，升金湖入湖口附近、上中湖区西北部和下湖悬浮物浓度相对较高，除夏季外升金湖悬浮物浓度均高于其连接长江段；在时间上，升金湖悬浮物浓度在夏季相对较低，在其他季节较高，而与其连接的长江水体呈现相反的年内变化规律；③闸控影响下河湖连通性改变造成的水位变化，是影响升金湖-长江悬浮物空间分异的关键因素.在平水期与枯水期，升金湖对长江悬浮物浓度变化具有一定的贡献度，而在丰水期，升金湖与长江悬浮物浓度变化之间的相关性不明显. |
| 英文摘要 |
| 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 (R2=0.863, RMSE=22.211 mg·L-1). 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. |
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