iCOAST: Integrated COASTal Sediment Systems

预测沿海形态在几十年时间尺度上的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”的基于过程的模型在短期内提供了关于水动力、泥沙输运和形态动力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，关注主要过程和调节海岸形态的反馈机制的行为系统模型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形式子集。iCoast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）新一代沿海行为系统模型，以及（iii）沿海系统制图的扩展方法，可用于将有关沿海行为的不同知识来源系统化和形式化。在iCoast中开发的所有软件都将是开源的，并与OpenMI兼容。研究集中在四个可交付成果上，这些可交付成果已被确定为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。French等人开发的沿海系统测绘的成功方法，将利用一种新的系统测绘工具，扩展并应用于整个英格兰和威尔士。这些新的海岸系统地图既可以取代目前在海岸线管理规划中使用的海岸单元和亚单元，也可以为更多的定量建模提供基于证据的框架。其中，水动力和泥沙运输沿海地区模式将在广泛的空间尺度上实施，以便提供波浪和潮汐强迫和泥沙路径的证据。该系统框架将在开源软件工具中实现，并与不确定性分析方法相结合。可交付成果2将提供新一代的行为地貌模块，这些模块可以连接起来，在中尺度上模拟耦合的海岸-河口-近海地貌行为。现有的降低复杂性的行为模块，其中一些由iCoast联盟内部持有（SCAPE， ASMITA，各种版本的1线海滩模型），将进行审查，并确定开发和增量改进机会。他们将由一个具有这类模型开发独特经验的团队进行深入研究。基于数据的模块的范围也将扩大，这些模块可以利用沿海天文台不断增长的数据集。这些模型将被集成到一个系统框架中，以研究涌现的特性和探索关键的敏感性。可交付成果3将需要应用和验证两个不同的沿海地区：萨福克海岸（子单元3c）和利物浦湾（子单元11a/11b），探索这些沿海地区对海平面上升、气候变化和沿海管理情景导致的沉积物供应变化的敏感性。这将产生高影响力出版物和示范所需的结果，这些结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、手册和知识转移讲习班，促进新方法的知识转移。我们的开源建模策略将在沿海研究界开创一种社区建模方法，与此同时，当沿海适应需求迫切需要新的预测能力时，从业者可以最大限度地获取所产生的知识。

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 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.