iCOAST: Integrated COASTal sediment systems

预测几十年时间尺度的海岸形态变化提出了科学挑战，目前还没有广泛适用的解决方案。然而，为了量化海岸侵蚀的风险，改进预测是必不可少的，海岸侵蚀本身就很重要，也是沿海洪水风险的主要媒介之一。虽然“自下而上”的过程为基础的模型提供了宝贵的证据，在短期内的水动力，沉积物运输和形态动力过程，其预测精度超过几十年的规模是目前从根本上有限的。与此同时，行为系统模型，重点是主要过程和反馈机制，调节海岸形态已被证明具有预测能力，在中尺度（10- 100 y和10 s-100 km），但到目前为止仅限于海岸形态的一个相当狭窄的子集。iCoast项目基于一个分层系统概念，该概念结合了（i）基于过程的模型的有益特征，（ii）新一代的海岸行为系统模型和（iii）海岸系统制图的扩展方法，可用于系统化和正式化关于海岸行为的不同知识来源。研究重点是四个可交付成果，这些成果已被确定为NERC自然灾害主题中的主要挑战：表1将是一个整体系统框架。French等人开发的沿海系统绘图的成功方法将利用一种新的系统绘图工具推广并适用于整个英格兰和威尔士。这些新的沿海系统地图既可以取代目前用于海岸线管理规划的沿海单元和子单元，又可以为更定量的建模提供一个以证据为基础的框架。其中，将在广阔的空间尺度上建立沿海地区的水动力和沉积物输运模型，以提供波浪和潮汐作用力以及沉积物路径的证据。该系统框架将在开放源码软件工具中实施，并与不确定性分析方法相结合。在适当的情况下，将在OpenMI中实现与专有工具的耦合。可扩展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耦合的海岸-河口-近海地貌行为。该可交付成果的工作将开始，首先审查现有的行为模块，其中一些模块在iCoast联盟内部（SCAPE、ASMITA、单线海滩模型的各种版本）。新开发和增量改进的优先事项将由具有此类模型开发独特经验的团队进行深入研究。可以利用沿海观测站快速扩展的数据集的基于数据的模型的范围将得到扩展。这些模型将被整合到一个系统框架内，以确定新出现的特性并探索关键的敏感性。（Sub-Cell 3c）和利物浦湾（子单元11 a和11 b），探讨这些沿海地区对海平面上升造成的沉积物供应变化的敏感性，气候变化和沿海管理情景。这些应用将产生影响力大的出版物所需的结果，以及建立对新方法付诸实践的信心所必不可少的示范。可持续发展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，同时最大限度地提高从业人员对沿海适应需求迫切需要新的预测能力时产生的知识的访问。

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.