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。该项目是对墨西哥湾碳氢化合物气泡羽流的特性和行为进行的实地和模拟研究。将观测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;羽流阶段环境水的夹带;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特性。这些结果对于理解预测海洋气候的碳氢化合物的自然来源和人为来源具有潜在的更广泛的影响。该项目还将涉及培训高中教师，重点是为机器人竞赛建造一个机器人水下航行器，该项目的重点是测量墨西哥湾天然渗漏的碳氢化合物羽流的气泡和湍流特性。所使用的技术包括从高频ADCP测量流动特性和从粒子跟踪（和成像）测速仪（PTV和PIV）测量气泡特性。这些观测结果将用于估计气泡尺寸分布、体积和动量通量、湍流和夹带以及初始上升期间的垂直上涌，以揭示与近床湍流特性和水文条件的潜在联系。将使用数值模拟来预测碳氢化合物在水柱和水面上的轨迹和分布。将利用卫星数据和测得的表面海流来估计浮油在海面的停留时间，以便与碳氢化合物在海面的最终结果的模型预测进行比较。总的来说，该项目将提高对控制气泡羽流和碳氢化合物渗漏和海洋环境中分散的夹带的物理机制的理解。该奖项反映了NSF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.