Hydrostatic Modeling of Buoyant Plumes

The Deepwater Horizon (DwH) oil spill in the Gulf of Mexico has led to increased interest in understanding point source convection dynamics in deep water. Most existing oil plume models use a Lagrangian based approach, which computes integral measures such as plume centerline trajectory and plume radius. However, by construction Lagrangian models neglect internal plume dynamics, as well as feedbacks of the buoyant plume on the ambient environment. We hypothesize that DwH-like plumes are dynamically active, and we use an Eulerian based convection model to test this hypothesis. We perform a series of hydrostatic numerical simulations to examine the dynamics of buoyant plumes in the presence of stratification, planetary rotation, and background cross flow. Initial results show that planetary rotation strongly affects the spreading buoyant plume and results in a modification of the plume trajectory relative to the background environment. In a quiescent environment, the buoyant plume becomes baroclinically unstable, resulting in anticyclonic vortex formation at the neutral buoyancy layer. After approximately 35 days, this vortex begins to propagate away from the buoyancy source. In the presence of a background cross flow, dynamically active bands of anticyclonic vorticity moving relative to the background flow appear at the neutral buoyancy layer. We also observe cyclonic vortex formation and propagation at several depths in the vicinity of the wellhead in a both a quiescent environment and an environment with a weak background cross flow. In addition, initial results show that by increasing planetary rotation in a quiescent environment, vortex formation and propagation occurs at a faster rate at all levels.