The migration of large-scale bed forms in an estuarine environment: observation and parameterisation for coastal area modelling

河口环境中大规模河床形态的迁移：沿海地区建模的观测和参数化

• 批准号: NE/F012306/1
• 金额: $ 8.93万
• 依托单位: Bangor University
• 依托单位国家: 英国
• 项目类别: Training Grant
• 财政年份: 2009
• 资助国家: 英国
• 起止时间: 2009 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=NE%2FF012306%2F1
• 关键词: migration; large; scale; bed; forms

CONTEXT. The topic of this proposal relates within Oceans 2025 to: Shelf and coastal processes: 13 'Morphological modelling in Liverpool Bay and adjacent estuaries'. It fits mainly under WP 3.5 'Coastal morphodynamics and bathymetric evolution', while contributing also to WP 9.1 'Assessing and improving the accuracy of shelf sea models'. In addition, this studentship will add significant value to the NERC-funded FORMOST project (NE/E015123/1, 2008-2010, involving Bangor University and POL) which aims to (i) extend POL's field observational capabilities in sediment transport research, and (ii) develop new parameterizations of local sediment transport, based on Bangor's Sand Transport Model, that will here be implemented in two coastal area models (Telemac and POLCOMS). The Telemac system has already been upgraded to include a parameterised version of the Bangor model, and this will be available to the student via FORMOST as a working tool for data interpretation. In addition, new field data will be obtained during FORMOST in the outer channels of the Dee Estuary, within the area of POL's Coastal Observatory, providing background information for the studentship. BACKGROUND. The migration of large-scale sedimentary features (sand waves, banks and bars) contributes significantly to the morphological evolution of the seabed. Such features are not resolved within coastal sediment transport models, giving rise to uncertainty in morphological outcomes. This project will focus on the mobility and migration of large-scale bed features in the Dee Estuary, examining the key physical processes largely from an observational standpoint, but including a modelling element that will allow an informed interpretation of the experimental outcomes. An understanding of the role of estuaries like the Dee in acting as sources or sinks for mobile sediment is essential from a management viewpoint against a background of climate change. The results of a pilot study carried out using POL's X-band radar during summer 2007 (MSc project, Bangor University, jointly-supervised by POL) indicate that large-scale sand features are advancing into the Dee Estuary in the intertidal area between Hilbre Island and the Wirral mainland. More generally, POL's radar, which is capable of monitoring the movement of bed forms over a 4 km radius, has revealed that large sand features are also advancing into the estuary in deeper water. However, what is unknown is the relative contribution of the respective large bed forms to the sediment budget of the Dee Estuary. The DETAILED AIMS of the studentship are to: (i) track sand dunes in the inter-tidal area near Hilbre Island, thus elaborating the results of the 2007 pilot study. This will highlight the role of waves and currents on net sediment transport. Interpretation of the results will include Telemac simulations for the conditions measured on site. (ii) track using X-band radar the movement of sand banks and dunes in deeper water in mid-estuary. Interpretation will be provided both by available/new ADCP data and modelling. Telemac (and possibly POLCOMS) will be used to establish the 'drivers' responsible for morphological change. (iii) establish a methodology for the inclusion of large-scale bed features in coastal area models, taking as a starting point Van Rijn's (2005) roughness formulation, introducing this into Telemac, and critically testing its effect with regard to the bed forms in the Dee. End users. The PhD programme will be of relevance to end users concerned with management issues in the Dee. For example, the Countryside Commission for Wales (CCW) as well as the Environment Agency (EA) will be in attendance at FORMOST project meetings to which the student will contribute. The study will also contribute directly to the Centre for Catchment and Coastal Research, part of the Partnership Project between Aberystwyth and Bangor Universities.

语境。该提案的主题与2025年海洋中有关：架子和沿海过程：13“利物浦湾和邻近河口的形态建模”。它主要适合WP 3.5“沿海形态动力学和测深的演化”，同时也有助于WP 9.1“评估和提高货架海模型的准确性”。此外，该学生验证将为NERC资助的Formost项目（NE/E/E015123/1，2008-2010，涉及Bangor University和POL），该项目旨在（i）扩展POL在Satement Transport Research中的现场观察能力，以及（ii）基于Bangor Sandom sanderm模型的新型参数（II）在此处建立了两种海岸（TEL），该领域是两种海岸（TEL）的新型参数，该领域是两种沿海地区（TEL）（TEL）的实施（TEL）。 Telemac系统已经升级到包含Bangor模型的参数化版本，这将通过Formost作为数据解释的工作工具提供给学生。此外，在POL沿海天文台区域内，将在Dee河口外部渠道的福里斯特期间获得新的现场数据，从而为学生提供背景信息。背景。大规模沉积特征（砂波，河岸和酒吧）的迁移对海床的形态演变产生了重大贡献。此类特征在沿海沉积物传输模型中无法解决，从而导致形态结局的不确定性。该项目将着重于DEE河口中大型床特征的移动性和迁移，从观察性的角度来看，主要检查了关键的物理过程，但包括一个建模元素，该元素将允许对实验结果进行明智的解释。从管理角度来看，对气候变化的背景，对Dee这样的河口在充当移动沉积物的来源的作用是至关重要的。一项在2007年夏季使用POL的X波段雷达进行的试点研究的结果（MSC项目，Bangor University，由POL共同监督）表明，大规模的沙子特征正在Hilbre Island和Wirral Maintland之间的潮汐区域中前进。更普遍的是，Pol的雷达能够监测半径4 km的床形式的运动，它表明，大的沙子特征也在更深的水中前进到河口。但是，未知的是各个大床形式对Dee河口的沉积物预算的相对贡献。该学生奖学金的详细目的是：（i）在希尔布雷岛附近的潮汐间区域跟踪沙丘，从而阐述了2007年的试点研究的结果。这将突出波和电流在净沉积物传输中的作用。结果的解释将包括针对现场测量条件的Telemac模拟。 （ii）使用X频段雷达轨迹轨迹在中旬较深的水中沙库和沙丘的运动。可用/新的ADCP数据和建模将提供解释。 Telemac（以及可能的Polcoms）将用于建立负责形态变化的“驱动因素”。 （iii）建立了一种在沿海地区模型中包含大规模床特征的方法，它是van Rijn（2005）的粗糙度配方的起点，将其引入Telemac，并严格测试其对DEE床形式的影响。最终用户。博士学位计划与与DEE中的管理问题有关的最终用户具有重要意义。例如，威尔士乡村委员会（CCW）以及环境局（EA）将参加学生将贡献的典型项目会议。该研究还将直接为集水和沿海研究中心做出贡献，这是Aberystwyth和Bangor大学之间合作项目的一部分。