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2017年德克萨斯州沿海登陆，并在5天内给德克萨斯州东南部带来125厘米的降雨，导致德克萨斯州大部分墨西哥湾沿岸地区以及休斯顿大都会地区和周边18个县发生灾难性洪水。水坝和水库在9月1日就满了水？这些大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11万亿加仑的淡水落下，最终这些淡水将被释放到广阔的德克萨斯大陆架上。仅在美国，除了密西西比河的排放之外，从未有过如此多的淡水影响沿海地区。密西西比河将东部的阿查法拉亚河和伯德福特三角洲分隔开来，并将淡水注入更窄的大陆架和墨西哥湾中北部更深的水域。快速反应项目的主要假设是，飓风哈维带来的淡水1)通过增加分层降低了沿海水质，从而抑制了大气氧气向地下水域的通风；2)通过从陆地来源运输营养物质，导致生物量和微生物活动增加，从而增加了呼吸作用。其次，当飓风哈维从墨西哥湾向大陆架地区移动时，德克萨斯湾地区的海洋热含量为风暴提供了热量，从而加剧了飓风哈维的强度。该项目将提供关键信息，了解飓风哈维的淡水径流如何影响沿海水域的分层、氧气和营养预算，以及这是否会导致缺氧和德克萨斯州大陆架沿线的其他长期生态影响。这些数据将迅速提供给其他研究人员、学生和公众。这个项目旨在回答两个重要的问题，这两个问题没有大洪水就无法回答。飓风哈维带来的淡水是否通过增加分层而降低了沿海水质，从而抑制了大气中氧气向背斜下海水的通风？它是否通过从陆地来源运输营养物质而增加了呼吸作用，从而增加了生物量和微生物活动？该项目还将试图确定德克萨斯州海湾地区的海洋热含量是否在飓风哈维从墨西哥湾向大陆架地区移动时为其提供热量，从而加剧了飓风的强度。这个快速反应项目将在R/V鹈鹕号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外，自主波浪滑翔机将采样网格以跟踪淡水羽流，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，并在飓风哈维之前的2017年6月和8月的两次巡航数据后进行。研究巡航将使用现有的近海观测系统，即德州自动浮标系统、德州高频雷达网络和德州农工大学浮力控制滑翔机项目，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做出反应。

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.