Seabed dynamics in a lage coastal embayment: 180 years of morphological change in the outer Thames estuary
Seabed dynamics in a lage coastal embayment: 180 years of morphological change in the outer Thames estuary
复制标题
大型沿海海湾的海底动态：泰晤士河口外 180 年来的形态变化
作者：
H. Burningham;J. French
本文分析了外泰晤士河海床的形态历史，从阿尔德堡（萨福克郡）到滨海绍森德（埃塞克斯）和马尔盖特（肯特），面积超过3,000平方公里。自十六世纪以来，该区域一直在测深图上绘制，自十八世纪以来，该区域一直在正式制图。自19世纪初以来出版的海图都包含了足够的格网参考或地面控制细节，以便在一个共同的坐标系（英国国家格网）上进行地理校正。因此，通过将测深数据数字化和插值到规则网格（3D表面）上，重建了外部海底的形态历史。利用断面、水深变化图和空间统计资料，研究了海底形态的演变。结果表明，海底行为存在相当大的空间变异性。在泰晤士河中部，银行经历了重大的深度变化，这可能与个别银行的横向变化有关。在这个区域的一些外侧堤表现出逐渐伸长。在整个萨福克海岸的银行位置的变化似乎更微妙，有证据表明，在这里的陆上和海上迁移。没有明确的证据表明，任何区域一致的反应，如海平面上升的大规模历史强迫。
This article analyses the morphological history of the outer Thames seabed, covering over 3,000 km2 from Aldeburgh (Suffolk), to Southend-on-Sea (Essex) and Margate (Kent). The region has been depicted on bathymetric charts since the sixteenth century, and has been formally charted since the eighteenth century. Charts published since the early 1800s incorporate sufficient grid reference or ground control detail for georectification onto a common coordinate system (British National Grid). The morphological history of the outer seabed was thus reconstructed through the digitisation and interpolation of soundings onto a regular grid (3D surface). The evolution of seabed morphology was examined using transects, bathymetric change maps and spatial statistics. The results show considerable spatial variability in seabed behaviour. Within the central Thames, banks have experienced significant depth changes can be associated with lateral shifts in individual banks. Some of the outer banks in this region exhibit progressive elongation. Shifts in bank position across the Suffolk shoreface appear to be more subtle, and there is evidence here of both onshore and offshore migration. There is no clear evidence of any regionally coherent response to large-scale historical forcing such as sea-level rise.