Examining hydrodynamics and connectivity resulting from atmospheric frontal passages in a coastal river delta

检查沿海河流三角洲大气锋面通道产生的流体动力学和连通性

基本信息

批准号：
2023443
负责人：
Matthew Hiatt
金额：
$ 37.84万
依托单位：
Louisiana State University
依托单位国家：
美国
项目类别：
Standard Grant
财政年份：
2021
资助国家：
美国
起止时间：
2021-01-01 至 2024-12-31
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=2023443&HistoricalAwards=false
关键词：
Examining hydrodynamics connectivity resulting atmospheric

项目摘要

This project aims to understand how cold fronts affect water movement in coastal river deltas. In regions with small tides, such as coastal Louisiana, winds associated with cold fronts are known to be important for circulating water and sediment throughout the region. However, scientists do not understand how water in complex coastal regions, such as coastal river deltas, respond to winds associated with cold fronts. Understanding this interaction is important, because cold fronts may contribute to coastal erosion, a major issue in Louisiana, and restoration efforts must account for the effects of cold fronts to be effective. This project will investigate these issues throughout coastal Louisiana using field measurements and modeling of wind events and water movement. In addition to improving the understanding of water circulation in complex coastal regions, the project will also engage stakeholders and delivers hands-on demonstrations to Baton Rouge (Louisiana) schoolchildren. Atmospheric cold fronts are major drivers of water circulation and sediment transport in coastal Louisiana, a region experiencing rapid land loss due to relative sea level rise, coastal erosion, and lack of sediment input. There is considerable interest in understanding and using natural deltaic processes through sediment diversions to mitigate land loss, as well as increased storm surge and saline intrusion. River deltas comprise relatively deep distributary channels and shallow wetlands that are hydraulically connected to channels. Previous analyses of the hydrodynamics resulting from frontal passages have focused on relatively homogeneous environments that do not have considerable changes in depth (e.g., the coastal shelf or open bays). Stark changes in depth, spatial gradients in connectivity, and the impact of fluvial versus marine forcings make river deltas a significantly more complex heterogeneous environment where cold front-induced circulation is not yet understood. This proposal will: 1) determine how water levels vary throughout frontal passages across the Mississippi Delta Region, 2) determine how appreciable changes in depth across a heterogenous delta affect hydrodynamics induced by cold fronts, and 3) identify the mechanisms that control channel-wetland connectivity in deltas during cold fronts. Synoptic analyses will focus on the coastal Louisiana region while detailed field measurements and numerical modeling will focus on the Wax Lake Delta in Louisiana. Outreach efforts include digital brochures distributed to local stakeholders and coastal managers, as well as a portable wind-driven wave tank that will be used in demonstrations engaging 200 undergraduate students and 2,500 K-8 students and teachers on an annual basis. This proposal is co-funded by the Hydrologic Sciences and Physical Oceanography programs.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.

该项目旨在了解冷锋如何影响沿海河三角洲的水运动。在路易斯安那州沿海潮汐的地区，与冷锋相关的风对于整个地区循环水和沉积物很重要。但是，科学家不了解复杂的沿海地区（例如沿海河三角洲）的水如何应对与冷阵线相关的风。了解这种互动很重要，因为冷锋可能导致沿海侵蚀，这是路易斯安那州的主要问题，并且恢复工作必须解释冷锋的影响。该项目将使用现场测量以及风事件和水运动的建模来调查整个路易斯安那州沿海地区的这些问题。除了提高对复杂沿海地区的水循环的理解外，该项目还将吸引利益相关者，并向巴吞鲁日（路易斯安那州）的小学生提供动手示威。大气冷锋是路易斯安那州沿海水流和沉积物运输的主要驱动因素，这是一个由于相对海平面上升，沿海侵蚀和缺乏沉积物输入而导致土地损失迅速的地区。通过沉积物转移来减轻土地损失，以及风暴潮和盐水侵入的增加，人们对理解和使用自然的三角洲过程具有很大的兴趣。河三角洲包括相对深的分布通道和浅水湿地，这些湿地与通道相连。先前对额叶通道产生的流体动力学的分析集中在相对均匀的环境上，这些环境没有深度变化（例如，沿海货架或开放式海湾）。深度变化，连通性的空间梯度以及河流与海洋强迫的影响使河三角洲成为一个更加复杂的异质环境，尚不清楚冷前诱导的循环。该提案将：1）确定在整个密西西比三角洲地区的整个正面通道中的水位如何变化，2）确定在寒冷阵线引起的异质三角洲的深度变化如何影响流体动力学，以及3）确定控制阵线的机制。概要分析将重点放在路易斯安那州沿海地区，而详细的现场测量和数值建模将集中在路易斯安那州的蜡湖三角洲。外展工作包括分发给当地利益相关者和沿海经理的数字手册，以及便携式风驱动的波浪坦克，将每年与200名本科生和2,500 K-8的学生和老师一起使用，该示范中使用。该提案由水文科学和物理海洋学计划共同资助。该奖项反映了NSF的法定任务，并使用基金会的知识分子优点和更广泛的影响标准，被认为值得通过评估来获得支持。