1996-2020年黄河口清水沟流路海岸线动态演变及其与水沙量的关系研究

Dynamic evolution and influencing factors of the shoreline of the Huanghe River Estuary from 1996 to 2020

海岸线演变及其动态监测对沿海地区生态保护和可持续发展至关重要。受自然过程和人类活动的影响,黄河三角洲海岸线始终处于动态变化之中。本文基于1996—2020年黄河口Landsat系列卫星影像,利用数字岸线分析系统(DSAS),探讨了近25年来黄河口海岸线动态演变规律及其对黄河输沙量变化的响应关系。研究发现:现行河口地区海岸线平均向海淤进速率为260m/a,老河口岸线平均变化速率为-167 m/a。调水调沙前,河口岸线整体处于蚀退阶段;调水调沙后,现行河口岸线初期快速淤进,后速率逐渐减缓,老河口始终处于蚀退状态。年内尺度上,现行河口岸线在调水调沙年份汛期前后淤进明显,非调水调沙年份汛期前后淤进缓慢,老河口岸线变化基本与年际变化一致。调水调沙前后,黄河入海泥沙量对岸线演变的影响程度加大,在年内尺度上对汛期前后现行河口岸线变化作用显著(R^(2)=0.93)。

It is vital for the ecological environment protection and sustainable development of coastal areas to explore the shoreline evolution and its dynamic monitoring.Affected by natural processes and human activities,the shoreline of the Huanghe River Delta is always in dynamic change.Based on the Landsat series of satellite images of the Huanghe River Estuary from 1996 to 2020,and using the Digital Shoreline Analysis System(DSAS),this paper discusses the dynamic evolution of the Huanghe River Estuary shoreline and its response to change in sediment discharge in the past 25 years.It is found that the shoreline in the active mouth was silted into the sea by an average of 260 m/a,and the average change of the old river mouth was-167 m/a.Before water-sediment regulation,the river mouth was in a state of retreat as a whole.After wate-sediment regulation,the active river mouth began to slit rapidly,and then the rate gradually slowed down,and the old river mouth was always in a state of retreat.On the intra-year scale,the active river mouth silted significantly around flood season in the year of water-sediment regulation,the deposition was slow around flood season in the year of non-water-sediment regulation.The change of the old river mouth was basically consistent with the inter-annual change.Around watersediment regulation,the influence of sediment discharge from the Huanghe River on the evolution of the shoreline was promoted,and the change of the active river mouth around flood season was related significandy on the intra-year scale(R^(2)=0.93).