各位老师、同学好，
LTO实验室学术报告（2019-52）：
报告题目：Horizontal Dispersion of Buoyant Materials in the Ocean Surface Boundary Layer
报告人：梁峻泓 (Professor, Department of Oceanography and Coastal Sciences & Center for Computation and Technology Louisiana State University )
主持人：王卫强研究员
时间：2019年12月26日（周四）下午15:00
地点：2号楼1201会议室
Many particulate matters in the ocean, such as spilled oil and microplastics are weakly buoyant. They constantly moves up and down in the ocean surface boundary layer despite their buoyancy. In this talk, I will discuss our recent study on the horizontal dispersion of materials under the exclusive influence of ocean surface boundary layer (OSBL) flows. The study is based on both three-dimensional turbulence-resolving Lagrangian particle trajectories and the classical theory of dispersion in bounded shear currents generalized for buoyant materials. Dispersion in the OSBL is caused by the vertical shear of mean horizontal currents and by the turbulent velocity fluctuations. Shear dispersion dominates turbulent dispersion for weakly buoyant materials. The effective horizontal diffusivity due to shear dispersion is controlled by multiple factors including wind speed, wave conditions, vertical diffusivity, mixed layer depth, latitude, and buoyant rising speed. With all other meteorological and hydrographic conditions being equal, the effective horizontal diffusivity is larger in wind-driven Ekman flows than in wave-driven Ekman-Stokes flows for weakly buoyant materials, and is smaller in Ekman flows than in Ekman-Stokes flows for strongly buoyant materials. The effective horizontal diffusivity is further reduced when enhanced mixing by breaking waves is included. The analytic framework will improve subgrid scale models in realistic particle trajectory models used to track spilled oil and microplastics.
附件下载：
