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，行为系统模型侧重于调节海岸形态的主要过程和反馈机制，已被证明具有中尺度（10-100年和10-100公里）的预测能力。然而，它们的应用仅限于相当狭窄的沿海地貌类型。 iCoast项目基于一个分层系统概念，它结合了（i）基于过程的模型的有益功能，（ii）新一代沿海行为系统模型，以及（iii）沿海系统映射的扩展方法，可用于系统化和正式化有关沿海行为的不同知识来源。所有在iCoast内开发的软件都将是开源和OpenMI兼容的。该研究的重点是已被确定为NERC自然灾害主题中的主要挑战的四个可交付成果：可交付成果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。 可扩展2将提供新一代的行为地貌模块，这些模块可以连接起来，以便在中尺度上模拟耦合的海岸-河口-近海地貌行为。将审查现有的降低复杂性的行为模块，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），并确定开发和增量改进机会。他们将由一个具有这种类型的模型开发独特经验的团队进行深入研究。还将扩大能够利用沿海观测站不断增加的数据集的数据模块的范围。这些模型将被整合到一个系统框架中，以研究紧急特性并探索关键的敏感性。 表3将涉及两个不同的沿海地区的应用和验证：萨福克海岸（子单元3c）和利物浦湾（子单元11 a/11 b），探索这些沿海地区的敏感性，造成海平面上升，气候变化和沿海管理方案的沉积物供应的变化。这将产生高影响力出版物所需的结果，并进行必要的示范，以建立对正在付诸实践的新方法的信心。 表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 the mesoscale (10-100 years and 10-100 km). However, their application has been limited to 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. All the software developed within iCoast will be open source and OpenMI compliant. 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. Deliverable 2 will provide a new generation of behavioural geomorphic modules, which can be linked to enable simulation of coupled coastal-estuary-offshore landform behaviour at a meso-scale. Existing reduced complexity behavioural modules, several of which are held in-house within the iCoast consortium (SCAPE, ASMITA, various versions of 1-line beach models) will be reviewed and development and incremental improvement opportunities will be identified. They will be researched intensively by a team with unique experience of this type of model development. The scope of data-based modules that can exploit the growing datasets from coastal observatories will also be extended. The models will be integrated within a systems framework in order to study emergent properties and explore key sensitivities. Deliverable 3 will entail application and validation of two distinct coastal regions: the Suffolk Coast (Sub-Cell 3c) and Liverpool Bay (Sub-Cells 11a/11b), exploring the sensitivities of these coastal regions to changes in sediment supply resulting from sea-level rise, climate change and coastal management scenarios. This 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.