海洋科学学术讲座预告第310期：A theory to include the effect of subsurface current on buoyant particles and its application to the study of river-borne Microplastics over the Louisiana/Texas continental shelf

报告内容简介：

        报告介绍主讲人最近的两项工作：（1）海洋上边界层物质输运和扩散的数学模型：这个模型基于流体力学理论，并得到高精度科学计算模型--大涡模拟的验证。（2）这个数学模型在墨西哥湾北部的海洋塑料追踪的应用：塑料是海洋上层主要污染物之一。对环境和生态系统有很大的负面影响。河流是海洋塑料的主要来源。传统塑料追踪模型不能区分微塑料（小于5毫米的塑料颗粒）和大型塑料（塑料瓶子，盖子，包装）。新的数学模型能从机理上区分微塑料和大型塑料的路径。结果显示，从密西西比河流出的微塑料和大型塑料在墨西哥湾有不同的路径。这个数学模型还能应用于溢油，浮游生物等海洋颗粒物的追踪。

Abstract:

        Surface currents are used in most Lagrangian tracking models for buoyant particles such as plastics and spilled oil. However, turbulence mixes buoyant particles into the ocean surface boundary layer. Subsurface current, which is different in both magnitude and direction from surface current, affects the transport and dispersion of buoyant particles. In this talk, I will present an analytic framework to model the transport and dispersion of buoyant particles including the effects of subsurface current. The analytic model was validated using solutions of a Large Eddy Simulation model. The analytic model was then implemented in the Larval TRANSport Lagrangian (LTRANS) model and was used to study the trajectories and fates of microplastics from the Mississippi and the Atchafalaya Rivers. Less buoyant plastic particles travel a longer distance for a longer period. Most river-borne plastic particles over the Louisiana/Texas continental shelf stop at the coast of Texas and Louisiana.

References:

Liang, J.-H., and co-authorsJ. Liu, M. Benfield, D. Justic, D. Holstein, B. Liu, R. Hetland, D. Kobashi, C. Dong and W. Dong (2021), Including the effects of subsurface currents on buoyant particles in Lagrangian particle tracking models: Model development and its application to the study of riverborne plastics over the Louisiana/Texas shelf. Ocean Modell., doi:10.1016/j.ocemod.2021.101879

Liang, J.-H., X. Wan, K. A. Rose, P. P. Sullivan, and J. C. McWilliams, (2018), Horizontal dispersion of buoyant materials in the ocean surface boundary layer. J. Phys. Oceanogr., 48(9), 2103-2125