RAPID: The impact of increased fresh water input from Hurricane Harvey to the water quality and stratification of coastal and offshore waters of Texas.

RAPID：飓风哈维增加的淡水输入对德克萨斯州沿海和近海水域的水质和分层的影响。

• 批准号: 1760381
• 负责人: Anthony Knap
• 金额: $ 19.96万
• 依托单位: Texas A&M University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-12-15 至 2018-11-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1760381&HistoricalAwards=false
• 关键词: RAPID; impact; increased; fresh; water

In late August 2017, Category 4 Hurricane Harvey made landfall on Coastal Texas, 2017 and stalled bringing 125 cm of rain to Southeastern Texas over a five-day period resulting in catastrophic flooding along most of the Gulf coast of Texas as well as the metropolitan Houston area and 18 surrounding counties. Dams and reservoirs filled and even on September 1st ? 3rd releases from these dams continued to flood the area releasing even more water. Approximately 11 trillion gallons were estimated to have fallen and eventually this freshwater will be released onto the broad Texas continental shelf. In the US alone there has never been so much fresh water impacting a coastal area other than the discharge of the Mississippi River, which divides between the Atchafalaya River and the Birdfoot Delta to the east and injects freshwater into a much narrower shelf and into much deeper water in the north-central Gulf. The main hypothesis of the Rapid response project is that freshwater from Hurricane Harvey has 1) reduced coastal water quality by increasing stratification, and thereby inhibiting ventilation of atmospheric oxygen to sub-surface waters and 2) increased respiration by transporting nutrients from terrestrially derived sources leading to increased biomass and microbial activity. Secondly, the ocean heat content of the Texas Bight region contributed to the intensification of Hurricane Harvey by supplying thermal heat to the storm as it passed from the deep Gulf of Mexico to the shelf region. This project will provide critical information on how freshwater runoff from hurricane Harvey is impacting the stratification, oxygen, nutrient budgets of the coastal waters and whether this could lead to hypoxia and other long-term ecological impacts along the Texas shelf. The data will be made available rapidly to other researchers, students and the public. This project aims to answer two questions of importance which could not be answered without a major flood. Is the freshwater from Hurricane Harvey reducing coastal water quality by increasing stratification, thereby inhibiting ventilation of atmospheric oxygen to subpycnocline water and is it increasing respiration by transporting nutrients from terrestrially derived sources leading to increased biomass and microbial activity? The project will also seek to determine if the ocean heat content of the Texas Bight region contributed to the intensification of Hurricane Harvey by supplying thermal heat to the storm as it passed from the deep Gulf of Mexico to the shelf region. This Rapid response project will conduct two research cruises on the R/V Pelican, one in late September and one in mid-November to quantify the effects and potential impacts of the freshwater run-off from Hurricane Harvey along the southern coast of Texas. In addition to the two cruises using a suite of oceanographic physio-chemical measurements, an autonomous Wave Glider will sample a grid to follow the freshwater plume and a buoyancy-controlled ocean glider will determine the depth and characteristics of the freshwater intrusion and its evolution between cruises and after data from two cruises in June and August 2017 prior to Hurricane Harvey. The research cruises will use existing offshore observing systems, i.e., the Texas Automated Buoy System, the Texas HF Radar network, and the Texas A&M University buoyancy-controlled glider program, to integrate the observations into a comprehensive picture of how the coastal region responded to the impulsive freshwater resulting from the unprecedented terrestrial flooding event in southeastern Texas.

2017 年 8 月下旬，2017 年 4 级飓风“哈维”在德克萨斯州沿海地区登陆，并在五天内给德克萨斯州东南部带来了 125 厘米的降雨，导致德克萨斯州墨西哥湾沿岸大部分地区以及休斯敦大都市地区和周边 18 个县发生灾难性洪水。水坝和水库已经填满，甚至在 9 月 1 日？这些水坝的第三次泄洪继续淹没该地区，释放出更多的水。据估计，大约有 11 万亿加仑的淡水流失，最终这些淡水将被释放到广阔的德克萨斯州大陆架上。仅在美国，除了密西西比河的泄洪之外，从来没有如此多的淡水影响沿海地区。密西西比河将阿查法拉亚河和东部的伯德富特三角洲分开，将淡水注入更狭窄的陆架和海湾中北部更深的水域。快速响应项目的主要假设是，飓风哈维产生的淡水：1）通过增加分层降低了沿海水质，从而抑制了大气中的氧气向地下水域的通气；2）通过从陆地来源输送营养物质而增加了呼吸作用，导致生物量和微生物活动增加。其次，德克萨斯湾地区的海洋热含量在飓风哈维从墨西哥湾深处向大陆架区域传播时向风暴提供热量，从而导致了飓风哈维的加剧。该项目将提供重要信息，说明飓风哈维的淡水径流如何影响沿海水域的分层、氧气和营养物预算，以及这是否会导致德克萨斯州大陆架缺氧和其他长期生态影响。这些数据将迅速提供给其他研究人员、学生和公众。该项目旨在回答两个重要问题，如果没有大洪水就无法回答这些问题。飓风“哈维”产生的淡水是否会通过增加分层从而抑制大气中的氧气向亚密斜水的通气而降低沿海水质，是否会通过从陆地来源输送营养物质而增加呼吸作用，从而导致生物量和微生物活动增加？该项目还将试图确定德克萨斯湾地区的海洋热含量是否通过在飓风哈维从墨西哥湾深处传播到陆架区域时向风暴提供热量而导致飓风哈维的加剧。该快速响应项目将在 R/V Pelican 上进行两次研究巡航，一次在 9 月下旬，一次在 11 月中旬，以量化飓风哈维沿德克萨斯州南部海岸的淡水径流的影响和潜在影响。除了使用一套海洋物理化学测量的两次巡航之外，自主波浪滑翔机还将对网格进行采样以跟踪淡水羽流，而浮力控制海洋滑翔机将确定淡水入侵的深度和特征及其在巡航之间以及在飓风哈维之前的两次巡航数据之后的演变。研究巡航将利用现有的近海观测系统，即德克萨斯州自动浮标系统、德克萨斯州高频雷达网络和德克萨斯农工大学的浮力控制滑翔机项目，将观测结果整合到一幅全面的图景中，了解沿海地区如何应对德克萨斯州东南部前所未有的陆地洪水事件造成的脉冲淡水。