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

2017年8月下旬，4级飓风哈维在德克萨斯州沿海登陆，并在五天内给德克萨斯州东南部带来125厘米的降雨，导致德克萨斯州墨西哥湾沿岸沿着大部分地区以及大都市休斯顿地区和周边18个县发生灾难性洪水。大坝和水库填满，甚至在9月1日？这些大坝的第三次释放继续淹没该地区，释放更多的水。据估计，大约有11万亿加仑的淡水下降，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，除了密西西比河的排放外，从来没有如此多的淡水影响过沿海地区，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，并将淡水注入到更窄的大陆架和更深的海湾中北部水域。快速反应项目的主要假设是，“哈维”飓风造成的淡水：1）由于分层增加，从而抑制了大气氧气向地下沃茨的通风，从而降低了沿海水质; 2）由于从陆地来源输送营养物质，导致生物量和微生物活动增加，从而增加了呼吸作用。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地区移动时为风暴提供了热量，从而促成了飓风哈维的强化。该项目将提供有关哈维飓风的淡水径流如何影响沿海沃茨的分层、氧气和营养收支的关键信息，以及这是否会导致德克萨斯州大陆架沿着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，这些问题就无法回答。哈维飓风产生的淡水是否通过增加分层而降低了沿海水质，从而抑制了大气氧气向密度跃层下的水的通风，是否通过从陆地来源输送营养物质而增加了呼吸作用，从而导致生物量和微生物活性增加？该项目还将寻求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经过到大陆架地区时向风暴提供热量而导致飓风哈维的加剧。这一快速反应项目将在“鹈鹕”号研究船上进行两次研究航行，一次在9月下旬，一次在11月中旬，以量化“哈维”飓风沿着得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外，自主波浪滑翔机将对网格进行采样以跟踪淡水羽流，浮力控制的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的演变，以及在飓风哈维之前的2017年6月和8月的两次巡航数据之后。研究航行将使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州A M大学浮力控制滑翔机计划，将观测结果整合到一个全面的画面中，以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冲击淡水。

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.