基于数字化海岸分析系统(DSAS)的海岸线变迁速率研究:以黄河三角洲和莱州湾海岸线为例

海岸线变化对海岸带生态环境改变、滨海土地侵蚀有着极其重要的影响,海岸线的提取和监测对海岸带生态系统的保护和管理具有重要意义。本研究基于数字化海岸线分析系统(DSAS,Digital Shoreline Analysis System),研究了黄河三角洲和莱州湾的海岸线时空变化规律。研究结果表明:通过提取1985-2015年6期的Landsat影像,发现近30年来黄河三角洲和莱州湾地区海岸线均呈现显著的向海方向扩张的趋势,且增长速率逐渐加快。黄河三角洲的终点变化速率(EPR,End Point Rate)约为73.0 m/a、线性回归速率(LRR,Linear Regression Rate)约为75.5 m/a,黄河港-大咀沟增长速度最快(129.2 m/a),受黄河泥沙输送的影响,黄河口和老黄河口岸线的几何形态呈现平滑的变化趋势;莱州湾岸线的EPR和LRR约为139.5 m/a和144.3 m/a,淄脉河河口-白浪河河口段增长速度最快(197.6 m/a),岸线变化较为显著的区域主要集中在港口、圈海堤坝、海水养殖等的地方。DSAS模型在海岸线定量化分析中具有显著优势,利用EPR和LRR指标能够科学有效地模拟岸线在时间和空间上的变化速率。

Study on the change rate of shoreline based on Digital Coastal Analysis System (DSAS): taking the shoreline of the Yellow River Deltaand Laizhou Bay as an example

The change of shoreline plays an important role in the coastal area ecological environment change and coastal land erosion. The extraction and monitoring of shoreline is of great significance to the protection and management of coastal ecosystem. Based on the Digital Shoreline Analysis System (DSAS), this paper studies the temporal and spatial variation of the shoreline of the Yellow River Delta and Laizhou Bay. Results show that: by extracting the Landsat 6 images from 1985 to 2015, it was found that the shoreline of the Yellow River Delta and Laizhou Bay showed a significant trend of expanding to the sea in the past 30 years, and the growth rate was accelerated. (1)The average of the End Point Rate(EPR) was about 73.0 m/a,and the linear regression rate (LRR) was about 75.48 m/a. The growth rate of the Yellow River port - Dazui ditch was the fastest (129.2 m/a). Due to the influence of the sediment transport in the Yellow River, the shoreline''s geometric shaped of the Yellow River estuary and the old Yellow River estuary showed a smooth trend; (2) The average growth in the Laizhou Bay was about 139.5 m/a (EPR) and 144.3 m/a (LRR). The growth rate of the Zimai-Bailang section was the fastest(197.6 m/a). The areas with relatively significant changed in shoreline are concentrated in areas such as ports, seawall dams, mariculture, etc.DSAS model had a significant advantage in the quantitative analysis of shoreline. EPR and LRR indicators can scientifically and effectively simulated the time and space rate of shoreline.