Land–sea interaction and morphogenesis of coastal foredunes — A modeling case study from the southern Baltic Sea coast
Land–sea interaction and morphogenesis of coastal foredunes — A modeling case study from the southern Baltic Sea coast
复制标题
DOI：
10.1016/j.coastaleng.2015.03.005
复制
发表时间：
2015-05
影响因子：
4.4
通讯作者：
Wenyan Zhang;Ralf Schneider;Jakob J. Kolb;T. Teichmann;Joanna Dudzinska-Nowak;J. Harff;T. Hanebuth
中科院分区：
文献类型：
--
作者：
Wenyan Zhang;Ralf Schneider;Jakob J. Kolb;T. Teichmann;Joanna Dudzinska-Nowak;J. Harff;T. Hanebuth
沿海前沙丘是多尺度海陆过程相互作用的结果。本文通过数值模式定量研究了海岸沙丘形态形成的基本驱动机制以及形成沙丘形态的自然过程和因素。通过元胞自动机（CA）方法模拟了海滩陆上部分的风成沉积物输运和植被生长，而在水下区的沉积物预算，作为沉积物源/汇的沙丘脊，估计在一个基于过程的模型。耦合模型被应用到一个1公里长的一段屏障海岸（Swina门）在波罗的海南部的61年（1951-2012年）后报其前沙丘的发展。观测数据和模拟结果之间的一般一致性，表明形成一个既定的沿海前沙丘的结果从风浪的影响和植被生长之间的平衡。在有效的向岸风和边界沉积物供应的驱动下，小规模沙丘在后滨发展并向陆地迁移。然后，它们被困在一个狭窄的地带，其特点是植被覆盖密度梯度大，将水动力活跃区和植被区分开。在这条地带，沉积物的不断积累导致了前沙丘脊的形成。根据模拟，既定沿海前沙丘的形成必须满足三个先决条件：1。有效的陆上风沙运输; 2.净陆上或侧向沉积物供应;以及3.有利于植物生长的气候。一个新的前沙丘脊的形成在前面已经存在的前沙丘是由沉积物的供应率，极端的风浪事件的频率和植被生长速率的组合。模拟结果表明，即使在沿着一个小的（1公里）海岸段的前沙丘的发展显着的变化，这意味着中长期的陆-海相互作用和前沙丘的形态发育是相当敏感的边界条件和各种过程作用于多时空尺度。
Coastal foredunes are developed as a result of the interplay of multi-scale land–sea processes. Basic driving mechanisms of coastal foredune morphogenesis as well as natural processes and factors involved in shaping the foredune geometry are quantitatively studied in this paper by a numerical model. Aeolian sediment transport and vegetation growth on the subaerial part of a beach is simulated by a cellular automata (CA) approach, while the sediment budget in the subaqueous zone, serving as a sediment source/sink for the foredune ridges, is estimated in a process-based model. The coupled model is applied to a 1 km-long section of a barrier coast (Swina Gate) in the southern Baltic Sea for a 61-year (1951–2012) hindcast of its foredune development. General consistency is shown between the observational data and simulation results, indicating that the formation of an established coastal foredune results from a balance between wind-wave impacts and vegetation growth. Driven by an effective onshore wind and a boundary sediment supply, small-scale dunes develop on the backshore and migrate landward. They are then trapped in a narrow strip characterized by a large density gradient of vegetation cover which separates the hydrodynamically-active zone and the vegetated zone. Continuous accumulation of sediment in this strip induces the development of a foredune ridge. According to the simulations, the formation of an established coastal foredune has to meet three preconditions: 1. an effective onshore aeolian transport; 2. a net onshore or lateral sediment supply; and 3. a climate favoring vegetation growth. The formation of a new foredune ridge in front of an already existing foredune is determined by a combination of the sediment supply rate, the extreme wind-wave event frequency and the vegetation growth rate. Simulation results demonstrate a remarkable variability in foredune development even along a small (1 km) coast section, implying that the medium-to-long term land–sea interaction and foredune morphogenesis is quite sensitive to boundary conditions and various processes acting on multi-temporal and spatial scales.