Collaborative Research: Temporal Variability of Vertical Upwelling of a Natural Hydrocarbon Seep and its Connection to the Ocean Surface

人们对海底碳氢化合物渗漏中甲烷和石油的自然释放知之甚少。本项目是对墨西哥湾油气气泡羽流的性质和行为进行实地和建模研究。将观察碳氢化合物气泡的特征，包括大小、上升速度和源附近的溶解；烟羽期环境水的夹带；以及到达海面的碳氢化合物的位置。该项目还将模拟单个气泡和羽流的特性。这些结果对了解自然与人为碳氢化合物来源，预测海洋气候具有潜在的更广泛的影响。该项目还将包括对高中教师的培训，重点是为机器人比赛建造一个机器人水下航行器。这个项目的重点是测量墨西哥湾自然渗漏的碳氢化合物羽流的气泡和湍流特性。使用的技术包括高频ADCP的流动特性测量和粒子跟踪（和成像）测速（PTV和PIV）的气泡特性测量。这些观测结果将用于估计气泡大小分布、体积和动量通量、湍流和夹带以及初始上升期间的垂直上升流，以揭示与近床湍流特征和水文条件的潜在联系。数值模拟将用于预测油气在水柱和地表的轨迹和分布。对浮油在海面停留时间的估计将使用卫星数据和测量的海面洋流，以与对海面碳氢化合物命运的模型预测进行比较。总的来说，该项目将提高对海洋环境中控制气泡羽流和碳氢化合物渗漏和扩散的物理机制的理解。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Natural release of methane and oil from hydrocarbon seeps in the ocean floor is poorly understood. This project is a field and modeling study of the properties and behavior of hydrocarbon bubble plumes in the Gulf of Mexico. Observations will be made of hydrocarbon bubble characteristics including size, rise velocity, and dissolution near the source; entrainment of ambient water in the plume phase; and the location of hydrocarbon that reaches the sea surface. The project will also model individual bubble and plume properties. The results have potential broader impacts for understanding natural versus anthropogenic sources of hydrocarbon for predicting ocean climate. The project will also involve training of high school teachers with a focus on building a robotic underwater vehicle for a robotics competition.This project focuses on measuring bubble and turbulent properties of hydrocarbon plumes from natural seeps in the Gulf of Mexico. The techniques to be used include measurements of flow characteristics from high frequency ADCP and of bubble characteristics from Particle Tracking (and Imaging) Velocimetry (PTV and PIV). These observations will be used to estimate bubble size distribution, volume and momentum fluxes, turbulence and entrainment, and vertical upwelling during the initial rise to reveal potential connections with the near-bed turbulence characteristic and hydrographic conditions. Numerical modeling will be used to predict the hydrocarbon trajectory and distribution in the water column and on the surface. Estimates of surface residence time for oil slicks will be made using satellite data and measured surface currents to compare to model predictions of the fate of hydrocarbons at the sea surface. Overall the project will improve understanding of the physical mechanisms that control bubble plumes and entrainment from hydrocarbon seeps and dispersion in the ocean 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.