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的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特性和行为的现场和模拟研究。将观察碳氢气泡的特征，包括气泡的大小、上升速度和在源头附近的溶解；周围水在羽流相中的夹带；以及到达海面的碳氢化合物的位置。该项目还将对单个气泡和羽流属性进行建模。这些结果可能对理解海洋气候预测中的自然和人为碳氢化合物来源产生更广泛的影响。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机器人水下机器人。该项目重点是测量墨西哥湾天然渗漏中碳氢化合物羽流的气泡和湍流特性。将使用的技术包括从高频ADCP测量流动特性，以及通过粒子跟踪(和成像)速度计(PTV和PIV)测量气泡特性。这些观测将被用来估计气泡尺寸分布、体积和动量通量、湍流和卷吸，以及在初始上升过程中的垂直上升流，以揭示与近床湍流特征和水文条件的潜在联系。数值模拟将被用来预测水柱和水面上的油气轨迹和分布。将利用卫星数据和测量的表面流估计浮油的表面停留时间，以与海面碳氢化合物去向的模型预测进行比较。总体而言，该项目将提高对控制海洋环境中气泡羽流以及碳氢化合物渗漏和扩散的物理机制的理解。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势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.