iCOAST: Integrated COASTal sediment systems

对几十年时间尺度上沿海地貌变化的预测提出了科学挑战，目前还没有广泛适用的解决方案。然而，改进预测对于量化海岸侵蚀风险至关重要，海岸侵蚀本身意义重大，也是沿海洪水风险的主要调停者之一。虽然基于“自下而上”过程的模型在短期内提供了关于水动力、泥沙输送和地貌动力学过程的有价值的证据，但它们在几十年尺度上的预测精度目前基本上是有限的。同时，集中于调节海岸形态的主要过程和反馈机制的行为系统模型已被证明在中尺度(10-100y和10s-100公里)具有预测能力，但到目前为止只在相当狭窄的海岸形态子集中具有预测能力。Ishore项目基于分层系统概念，该概念结合了(I)基于过程的模型的有益特征，(Ii)新一代海岸行为系统模型和(Iii)海岸系统绘图的扩展方法，可用于系统化和正规化关于海岸行为的不同知识来源。研究集中在四项可交付成果上，这些成果已被确定为NERC自然灾害主题中的主要挑战：可交付成果1将是一个整体系统框架。弗兰奇等人开发的沿海系统测绘的成功方法。利用一种新的系统测绘工具，将推广和应用于英格兰和威尔士的所有地区。这些新的沿海系统图既可以取代目前在海岸线管理规划中使用的沿海单元和子单元，也可以为更定量的建模提供一个基于证据的框架。其中，将在广泛的空间尺度上实施沿海地区的水动力和泥沙输送模型，以提供波浪和潮汐强迫以及泥沙路径的证据。系统框架将在开放源码软件工具中实施，并辅之以不确定度分析方法。在适当情况下，将在OpenMI中实施与专有工具的结合。可交付的2将是新一代降低复杂性的行为地貌模型，以便能够在中尺度上模拟海岸-河口-近海耦合的地貌行为。这项可交付成果的工作将从审查现有的行为模块开始，其中几个模块是在Ishore财团(SCAPE、Asmita、各种版本的1-line海滩模型)内部进行的。确定的新开发和增量改进的优先事项将由一个在这类模型开发方面具有独特经验的团队深入研究。可以利用沿海观测站迅速扩大的数据集的基于数据的模型的范围将扩大。这些模型将被整合到一个系统框架内，以确定紧急性质并探索关键的敏感性。交付方案3将要求在两个沿海地区，即萨福克海岸(次级单元3c)和利物浦湾(次级单元11a和11b)进行应用和验证，探索这些沿海区域对海平面上升、气候变化和海岸管理情景引起的沉积物供应变化的敏感性。这些应用程序将产生高影响力出版和示范所需的成果，这些成果对于建立对正在付诸实践的新办法的信心至关重要。可交付成果4将通过一系列传播机制，包括教程、手册和知识转让讲习班，促进新方法的知识转让。我们的开源建模战略将在沿海研究界启动社区建模方法，同时最大限度地让实践者获得在海岸适应需求迫切需要新的预测能力时产生的知识。

Prediction of changing coastal morphology over timescales of decades raises scientific challenges to which there are not yet widely applicable solutions. Yet improved predictions are essential in order to quantify the risk of coastal erosion, which is significant in its own right and also one of the main mediators of coastal flood risk. Whilst 'bottom-up' process-based models provide valuable evidence about hydrodynamic, sediment transport and morphodynamic processes in the short term, their predictive accuracy over scales of decades is for the time being fundamentally limited. Meanwhile, behavioural systems models, that focus on the main processes and feedback mechanisms that regulate coastal form have been shown to have predictive capability at a mesoscale (10-100y and 10s-100km) but so far only in a rather narrow sub-set of coastal forms.The iCoast project is based upon a hierarchical systems concept which combines (i) the beneficial features of process-based models, (ii) a new generation of coastal behavioural systems models and (iii) an extended approach to coastal systems mapping, which can be used to systematise and formalise different sources of knowledge about coastal behaviour.The research is focussed upon four deliverables that have been identified as major challenges in the NERC Natural Hazards Theme:Deliverable 1 will be an overall systems framework. The successful approach to coastal systems mapping developed by French et al. will be extended and applied to all of the England and Wales, making use of a new systems mapping tool. These new coastal systems maps can both supersede the coastal cells and sub-cells currently used in shoreline management planning and provide an evidence-based framework for more quantitative modelling. Therein, hydrodynamic and sediment transport coastal area models will be implemented at a broad spatial scale in order to provide evidence of wave and tidal forcings and sediment pathways. The systems framework will be implemented in open source software tools and coupled with methods for uncertainty analysis. Coupling with proprietary tools will, where appropriate, be implemented in OpenMI.Deliverable 2 will be a new generation of reduced complexity behavioural geomorphic models to enable simulation of coupled coastal-estuary-offshore landform behaviour at a meso-scale. Work on this deliverable will begin by reviewing existing behavioural modules, several of which are held in-house within the iCoast consortium (SCAPE, ASMITA, various version of 1-line beach models). Identified priorities for new development and incremental improvement will be researched intensively by a team with unique experience of this type of model development. The scope of data-based models that can exploit the rapidly expanding datasets from coastal observatories will be extended. The models will be integrated within a systems framework in order to identify emergent properties and explore key sensitivities.Deliverable 3 will entail application and validation at two coastal regions, namely the Suffolk Coast (Sub-Cell 3c) and Liverpool Bay (Sub-Cells 11a and 11b), exploring the sensitivities of these coastal regions to changes in sediment supply resulting from sea-level rise, climate change and coastal management scenarios. These applications will yield the results needed for high impact publication and the demonstrations that are essential to build confidence in new approaches being transferred into practice.Deliverable 4 will facilitate knowledge transfer of the new methods through a range of dissemination mechanisms, including tutorials, manuals and knowledge transfer workshops. Our open source modelling strategy will initiate a community modelling approach in the coastal research community, at the same time as maximising access by practitioners to the knowledge generated at a time when requirements for coastal adaptation urgently require new predictive capability.