PREEVENTS Track 2: Collaborative Research: A Dynamic Unified Framework for Hurricane Storm Surge Analysis and Prediction Spanning across the Coastal Floodplain and Ocean

风暴驱动的沿海洪水受到许多物理过程的影响，包括河流排放，区域降雨，风，大气压力，波浪引起的设置，波浪爬高，潮汐和波动的基线海洋水位。操作风暴潮模型，如NOAA的海洋预测中心（Extratrophic Surge and Tide Operational Forecast System）使用的模型，包含了各种各样的过程，包括河流排放、大气风和压力、波浪和潮汐。然而，沿海涌浪模型通常不包括降雨的影响，在沿海洪泛区，也没有波动的背景水位，由于海洋密度结构。尽管如此，洪泛区水文和海洋基线水位提供了对河流和河口环境的重要控制（例如，2017年飓风哈维期间在休斯顿大都会地区和2018年飓风佛罗伦萨期间在北卡罗来纳州看到的戏剧性影响）。最近的事件表明，一个统一的方法，包括所有相关的物理过程是至关重要的准确预测模拟沿海洪水由于极端事件。该项目将通过将水文学，水力学和波浪融合到一个动态统一的计算框架中来应对这一挑战，该框架使用从深海到高地地区和沿海洪泛区的非结构化网格。提高洪水风险管理人员、保险业和城市规划者评估整个沿海洪泛区洪水风险的能力。改进后的模型将为开发和建设实践提供更好的指导，有助于提高城市的复原力，并降低沿海人口和基础设施的风险。此外，这项工作将改善沿海洪水预报，使联邦、州和地方灾害管理人员能够优化发布疏散和应急计划的警报。该项目促进的海洋环流、沿海流体动力学和水文建模社区之间的合作将有助于支持雄心勃勃的项目，如NOAA国家水中心的国家综合水模型，该模型正处于水文学和沿海流体动力学整合的初步阶段。在水文学，沿海流体动力学，物理海洋学和计算数学的交叉点培训学生，以帮助开发和应用学术界越来越复杂和先进的模型，建议的统一框架将通过综合考虑降雨量来改善预测的水位梯度和整个沿海洪泛区的流量，沿海洪泛区内的驱动水文以及提高本底开阔洋水位。发展完善但粗糙的全球海洋模型将不均匀地耦合到高分辨率二维浅水方程模型，以考虑影响沿海水位的大尺度斜压海洋过程。将开发异质物理之间的接口策略和条件，使接口在时间和空间上移动的物理范围从干燥到地表径流加压流。随着风暴的演变，应用正确的物理和相关的数学模型将产生更强大、更准确的模型，以及更有效的模型。这将动态地说明水在洪泛区的水文-水动力相互作用。动态负载平衡将占广泛变化的计算（CPU）成本为每一组物理和物理的动态迁移将在异构并行计算环境中实施。这个奖项反映了NSF的法定使命，并已被认为是值得通过使用基金会的智力价值和更广泛的影响审查标准进行评估的支持。

Storm-driven coastal flooding is influenced by many physical processes including riverine discharges, regional rainfall, wind, atmospheric pressure, wave-induced set up, wave runup, tides, and fluctuating baseline ocean water levels. Operational storm surge models such as those used by NOAA's Ocean Prediction Center (Extratropical Surge and Tide Operational Forecast System) incorporate a variety of these processes including riverine discharges, atmospheric winds and pressure, waves, and tides. However, coastal surge models do not typically incorporate the impact of rainfall across the coastal floodplain nor fluctuations in background water levels due to the oceanic density structure. Nonetheless, the floodplain hydrology and ocean baseline water levels provide vital controls in riverine and estuarine environments (e.g., the dramatic effect seen in the Houston metropolitan region during Hurricane Harvey in 2017 and in North Carolina during Hurricane Florence in 2018). Recent events have shown that a unified approach that incorporates all the relevant physical processes is critical for accurate predictive simulations of coastal flooding due to extreme events. This project will tackle this challenge by melding hydrology, hydraulics, and waves into a dynamic unified computational framework that uses unstructured meshes spanning from the deep ocean to upland areas and across the coastal floodplain. Improved capacity for flood risk managers, the insurance industry, and city planners to evaluate flood risk across the entire coastal floodplain. Improved models will lead to better guidance on development and construction practices, will help make cities more resilient and will reduce risk for coastal populations and infrastructure. In addition, this work will improve coastal flood forecasting enabling federal, state, and local disaster managers, to optimize issuing warnings for evacuation and emergency planning. The collaboration between the ocean circulation, coastal hydrodynamics, and hydrology modeling communities fostered by this project will help support ambitious projects such as NOAA's National Water Center's National Integrated Water Model, which is at the preliminary stages of integration of hydrology and coastal hydrodynamics. Training of students at the intersection of hydrology, coastal hydrodynamics, physical oceanography, and computational mathematics, to help develop and apply ever-more complex and advanced models in academia, government and industry.The proposed unified framework will improve the predicted water level gradient and flows throughout the coastal floodplain by integrally considering the rainfall-driven hydrology within the coastal floodplain as well as improving the background open ocean water level. Well-developed but coarse global ocean models will be heterogeneously coupled to high-resolution 2D shallow water equation models in order to account for large-scale baroclinic ocean processes that impact coastal water levels. Interface strategies and conditions between heterogeneous physics will be developed that allow the interfaces to move in time and space for the range of physics from dry to surface runoff to pressurized flow. Applying the right physics and associated mathematical models as the storms evolve will result in more robust and accurate models, as well as much more efficient models. This will dynamically account for the hydrologic - hydrodynamic interaction of water across the floodplain. Dynamic load balancing will account for widely varying computational (CPU) costs for each set of physics and the dynamic migration of the physics will be implemented within the heterogeneous parallel computing environment.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.